Nov. 2000, 応用物理学会, 第61回秋期応用物理学会学術講演会『講演奨励賞』　　　　　　　　　　　　　　　
化合物半導体ナノショットキー界面の電気的特性とその制御
佐藤 威友

Dec. 1997, 電気関係学会北海道支部会, 平成9年度『若手講演者賞』　　　　　　　　　　　　　　　
In situ 電気化学プロセスを用いたショットキー障壁の形成
佐藤 威友

Low interface state density in Al₂O₃/n-GaN MOS capacitors with rapid deposition of Al₂O₃ gate insulator fabricated via mist-CVD
Hadirah A. Radzuan, Masaya Fukumitsu, Ryota Ochi, Yusui Nakamura, Taketomo Sato, Zenji Yatabe
Japanese Journal of Applied Physics, 64, 7, 070906, 070906, IOP Publishing, 01 Jul. 2025, [Peer-reviewed]
English, Scientific journal, Abstract

This study highlights the potential of mist chemical vapor deposition (mist-CVD) as an eco-friendly, cost-effective gate insulator deposition method for GaN-based metal-oxide-semiconductor (MOS) devices. We deposited an Al₂O₃ gate insulator on homoepitaxial n-GaN structures via mist-CVD. We found that mist-CVD achieved a deposition rate of 30 nm min⁻¹. From an admittance analysis, quantitative characterizations confirmed low interface state density at the Al₂O₃/n-GaN interface near the conduction band edge, in the range of 10¹⁰ cm⁻²eV⁻¹. These findings demonstrate that mist-CVD exhibits performance comparable to the conventional deposition method, atomic layer deposition, highlighting the potential of mist-CVD for GaN-based MOS device applications.

Improvement of the fabrication process for top-down GaN nanowires using contactless photo-assisted electrochemical etching
Hisahiro Furuuchi, Taketomo Sato, Junichi Motohisa
Japanese Journal of Applied Physics, 64, 3, 03SP02, 03SP02, IOP Publishing, 01 Mar. 2025, [Peer-reviewed]
Scientific journal, Abstract

Contactless photo-assisted electrochemical (CL-PEC) etching and successive alkaline solution treatment were applied for the fabrication of GaN nanowires (NWs) using a top-down approach. By using Cr as an etching mask instead of the Ti used in the previous study, miniaturization of the size, as well as the improvement of the uniformity in shape and size, was achieved, and GaN NWs with an average diameter of 59 nm were obtained. We also attempted to increase the etching rate by installing an additional UVA light source in the etching system and achieved a shorter processing time by a factor of approximately two.

Effects of SiO₂ cap annealing on MOS interfaces formed on Mg-doped p-type GaN surface
Yining Jiao, Masanobu Takahashi, Taketomo Sato, Masamichi Akazawa
Japanese Journal of Applied Physics, 63, 9, 09SP19, 09SP19, IOP Publishing, 02 Sep. 2024
Scientific journal, Abstract

In this paper, we report the effects of 800 °C SiO₂ cap annealing on the Al₂O₃/p-type GaN (p-GaN):Mg and SiO₂/p-GaN:Mg interfaces formed at relatively low temperatures, as determined by X-ray photoelectron spectroscopy (XPS) and sub-bandgap-light-assisted capacitance–voltage (C–V) measurement. For the sample with capless annealing at 800 °C and subsequent HF treatment before the Al₂O₃/p-GaN interface formation by atomic layer deposition at 300 °C, its C–V characteristics indicated the existence of high-density midgap states. By SiO₂ cap annealing and subsequent HF treatment to remove the cap layer, we found that the Al₂O₃/p-GaN interface showed a reduction in midgap state density. The same effect was confirmed at the SiO₂/p-GaN interface. Taking this finding and XPS results together, we consider the possibility that SiO₂ cap annealing at 800 °C and the subsequent HF treatment prior to the formation of the Al₂O₃/p-GaN and SiO₂/p-GaN interfaces led to the reduction of interface disorder.

Reduction in Gap State Density near Valence Band Edge at Al2O3/p-type GaN Interface by Photoelectrochemical Etching and Subsequent SiO2 Cap Annealing
Yining Jiao, Takahide Nukariya, Umi Takatsu, Tetsuo Narita, Tetsu Kachi, Taketomo Sato, Masamichi Akazawa
Physica Status Solidi (B) Basic Research, 2024
Scientific journal

Investigation of dominance in near-surface region on electrical properties of AlGaN/GaN heterostructures using TLM, XPS, and PEC etching techniques
Ryota Ochi, Takuya Togashi, Yoshito Osawa, Fumimasa Horikiri, Hajime Fujikura, Kazunari Fujikawa, Takashi Furuya, Ryota Isono, Masamichi Akazawa, Taketomo Sato
Applied Physics Express, 16, 9, 091002-1, 091002-2, IOP, Sep. 2023, [Peer-reviewed], [International Magazine]
English, Scientific journal

Detection of defect levels in vicinity of Al2O3/ p-type GaN interface using sub-bandgaplight- assisted capacitance–voltage method
Masamichi Akazawa, Yuya Tamamura, Takahide Nukariya, Kouta Kubo, Taketomo Sato, Tetsuo Narita, Tetsu Kachi
Journal of Applied Physics, 132, 19, 195302-1, 195302-10, 16 Nov. 2022, [Peer-reviewed], [International Magazine]
English, Scientific journal

Fabrication of GaN nanowires containing n+-doped top layer by wet processes using electrodeless photo-assisted electrochemical etching and alkaline solution treatment
Michihito Shimauchi, Kazuki Miwa, Masachika Toguchi, Taketomo SATO, Junichi Motohisa
Applied Physics Express, IOP Publishing, 06 Oct. 2021, [Peer-reviewed]
English, Scientific journal

Self-terminating contactless photo-electrochemical (CL-PEC) etching for fabricating highly uniform recessed-gate AlGaN/GaN high-electron-mobility transistors (HEMTs)
Masachika Toguchi, Kazuki Miwa, Fumimasa Horikiri, Noboru Fukuhara, Yoshinobu Narita, Osamu Ichikawa, Ryota Isono, Takeshi Tanaka, Taketomo Sato
Journal of Applied Physics, 130, 2, 024501, 024501, AIP Publishing, 14 Jul. 2021, [Peer-reviewed], [Last author]
English, Scientific journal

HfSiOx-gate GaN MOS-HEMTs for RF power transistor
Tamotsu Hashizume, Ryota Ochi, Erika Maeda, Toshihide Nabatame, Koji Shiozaki, Taketomo Sato
Proceedings of SPIE - The International Society for Optical Engineering, 11686, 2021
International conference proceedings

Fabrication of Recessed-Gate AlGaN/GaN Hemts Utilizing Contactless Photo-Electrochemical (CL-PEC) Etching
Masachika Toguchi, Kazuki Miwa, Fumimasa Horikiri, Noboru Fukuhara, Yoshinobu Narita, Osamu Ichikawa, Ryota Isono, Takeshi Tanaka, Taketomo Sato
ECS Meeting Abstracts, 68th, 23 Nov. 2020, [Last author]

(Invited) Photo-Electrochemical Etching and Porosification of III-Nitride Semiconductors
Taketomo Sato, Masachika Toguchi
ECS Meeting Abstracts, 23 Nov. 2020, [Invited], [Lead author]
International conference proceedings

Depth profiling of surface damage in n-type GaN induced by inductively coupled plasma reactive ion etching using photo-electrochemical techniques
Shinji Yamada, Kentaro Takeda, Masachika Toguchi, Hideki Sakurai, Toshiyuki Nakamura, Jun Suda, Tetsu Kachi, Taketomo Sato
Applied Physics Express, 13, 10, 106505, 106505, IOP Publishing, 01 Oct. 2020, [Peer-reviewed], [Last author]
English, Scientific journal

Gate controllability of HfSiOx/AlGaN/GaN MOS high-electron-mobility transistor
Ryota Ochi, Erika Maeda, Toshihide Nabatame, Koji Shiozaki, Taketomo Sato, Tamotsu Hashizume
AIP Advances, 10, 6, 065215, 065215, AIP Publishing, 01 Jun. 2020, [Peer-reviewed]
Scientific journal

Thermal-assisted contactless photoelectrochemical etching for GaN
Fumimasa Horikiri, Noboru Fukuhara, Hiroshi Ohta, Naomi Asai, Yoshinobu Narita, Takehiro Yoshida, Tomoyoshi Mishima, Masachika Toguchi, Kazuki Miwa, Hiroki Ogami, Taketomo Sato
Applied Physics Express, 13, 4, 01 Apr. 2020
Scientific journal

Self-termination of contactless photo-electrochemical (PEC) etching on aluminum gallium nitride/gallium nitride heterostructures
Kazuki Miwa, Yuto Komatsu, Masachika Toguchi, Fumimasa Horikiri, Noboru Fukuhara, Yoshinobu Narita, Osamu Ichikawa, Ryota Isono, Takeshi Tanaka, Taketomo Sato
Applied Physics Express, 13, 2, 026508, 026508, IOP Publishing, 01 Feb. 2020, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal

Fabrication of recessed structures for GaN HEMTs by a simple wet etching process
Fumimasa Horikiri, Noboru Fukuhara, Masachika Toguchi, Kazuki Miwa, Yoshinobu Narita, Osamu Ichikawa, Ryota Isono, Takeshi Tanaka, Taketomo Sato
CS MANTECH 2020 - 2020 International Conference on Compound Semiconductor Manufacturing Technology, Digest of Papers, 127, 130, 2020
International conference proceedings

Photoelectrochemical Etching Technology for Gallium Nitride Power and RF Devices
Fumimasa Horikiri, Noboru Fukuhara, Hiroshi Ohta, Naomi Asai, Yoshinobu Narita, Takehiro Yoshida, Tomoyoshi Mishima, Masachika Toguchi, Kazuki Miwa, Taketomo Sato
IEEE Transactions on Semiconductor Manufacturing, 32, 4, 489, 495, Institute of Electrical and Electronics Engineers ({IEEE}), Oct. 2019, [Peer-reviewed]
English, Scientific journal

Low-Damage Etching for AlGaN/GaN HEMTs Using Photo-Electrochemical Reactions
Taketomo Sato, Masachika Toguchi, Yuto Komatsu, Keisuke Uemura
IEEE Transactions on Semiconductor Manufacturing, 32, 4, 483, 488, Institute of Electrical and Electronics Engineers ({IEEE}), Aug. 2019, [Peer-reviewed]
English, Scientific journal

Anisotropic Electrochemical Etching of Porous Gallium Nitride by Sub-Bandgap Absorption Due to Franz-Keldysh Effect
Masachika Toguchi, Kazuki Miwa, Taketomo Sato
Journal of The Electrochemical Society, 166, 12, H510, H512, The Electrochemical Society, Jul. 2019, [Peer-reviewed]
English, Scientific journal

Electrodeless photo-assisted electrochemical etching of GaN using a H3PO4-based solution containing S2O82– ions　　　　　　　　　　　　　　　
Masachika Toguchi, Kazuki Miwa, Fumimasa Horikiri, Noboru Fukuhara, Yoshinobu Narita, Takehiro Yoshida, Taketomo Sato
Applied Physics Express, 12, 066504-1, 066504-4, May 2019, [Peer-reviewed]
English, Scientific journal

Effect of photoelectrochemical etching and post-metallization annealing on gate controllability of AlGaN/GaN high electron mobility transistors
Keisuke Uemura, Manato Deki, Yoshio Honda, Hiroshi Amano, Taketomo Sato
Japanese Journal of Applied Physics, 58, SC, SCCD20-1, SCCD20-6, May 2019, [Peer-reviewed]
English, Scientific journal

Simple wet-etching technology for GaN using an electrodeless photo-assisted electrochemical reaction with a luminous array film as the UV source
Horikiri Fumimasa, Fukuhara Noboru, Ohta Hiroshi, Asai Naomi, Narita Yoshinobu, Yoshida Takehiro, Mishima Tomoyoshi, Toguchi Masachika, Miwa Kazuki, Sato Taketomo
APPLIED PHYSICS EXPRESS, 12, 3, 01 Mar. 2019, [Peer-reviewed]

Effects of a photo-assisted electrochemical etching process removing dry-etching damage in GaN
Matsumoto Satoru, Toguchi Masachika, Takeda Kentaro, Narita Tetsuo, Kachi Tetsu, Sato Taketomo
JAPANESE JOURNAL OF APPLIED PHYSICS, 57, 12, Dec. 2018, [Peer-reviewed]

新規製造現場での基盤技術 光電気化学反応を利用した半導体の低損傷加工と高精度エッチング技術
佐藤威友
ケミカルエンジニヤリング, 63, 6, 399‐405, 405, 川崎 : 化学工業社, Jun. 2018, [Invited]
Japanese

Electrochemical formation and application of porous gallium nitride
Taketomo Sato, Masachika Toguchi
ECS Transactions, 86, 1, 3, 14, Electrochemical Society Inc., 2018
English, International conference proceedings

Low-damage etching of nitride semiconductors utilizing photo-electrochemical reactions for electron devices
植村圭佑, 松本悟, 渡久地政周, 伊藤圭亮, 佐藤威友, 佐藤威友
電子情報通信学会技術研究報告, 117, 331(ED2017 49-71), 23‐26, 26, 電子情報通信学会, 23 Nov. 2017
Japanese, Scientific journal

Precise thickness control in recess etching of AlGaN/GaN hetero-structure using photocarrier-regulated electrochemical process
Yusuke Kumazaki, Keisuke Uemura, Taketomo Sato, Tamotsu Hashizume
JOURNAL OF APPLIED PHYSICS, 121, 18, May 2017, [Peer-reviewed]
English, Scientific journal

Precise Structural Control of GaN Porous Nanostructures Utilizing Anisotropic Electrochemical and Chemical Etching for the Optical and Photoelectrochemical Applications
Yusuke Kumazaki, Satoru Matsumoto, Taketomo Sato
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 164, 7, II477, II483, 2017, [Peer-reviewed]
English, Scientific journal

Low-damage Recess Etching of AlGaN/GaN Hetero-structure by Electrochemical Process
熊崎祐介, 植村圭佑, 佐藤威友
電子情報通信学会技術研究報告, 116, 357(CPM2016 90-112), 45‐50, 50, 05 Dec. 2016
Japanese, Scientific journal

Formation of GaN porous structures with improved structural controllability by photoassisted electrochemical etching
Yusuke Kumazaki, Zenji Yatabe, Taketomo Sato
JAPANESE JOURNAL OF APPLIED PHYSICS, 55, 4, 04EJ12, Apr. 2016, [Peer-reviewed]
English, Scientific journal

Electrochemical Formation of N-type GaN and N-type InP Porous Structures for Chemical Sensor Applications
Taketomo Sato, Xiaoyi Zhang, Keisuke Ito, Satoru Matsumoto, Yusuke Kumazaki
2016 IEEE SENSORS, 2016, [Peer-reviewed]
English, International conference proceedings

Interface control technologies for high-power GaN transistors - Self-stopping etching of p-GaN layers utilizing electrochemical reactions
Taketomo Sato, Yusuke Kumazaki, Masaaki Edamoto, Masamichi Akazawa, Tamotsu Hashizume
GALLIUM NITRIDE MATERIALS AND DEVICES XI, 9748, 97480Y, 2016, [Peer-reviewed], [Invited]
English, International conference proceedings

Large photocurrents in GaN porous structures with a redshift of the photoabsorption edge
Taketomo Sato, Yusuke Kumazaki, Hirofumi Kida, Akio Watanabe, Zenji Yatabe, Soichiro Matsuda
SEMICONDUCTOR SCIENCE AND TECHNOLOGY, 31, 1, Jan. 2016, [Peer-reviewed]
English, Scientific journal

Electrochemical formation and UV photoresponse properties of GaN porous structures
Hirofumi Kida, Yusuke Kumazaki, Zenji Yatabe, Taketomo Sato
IEICE technical report. Electron devices, 115, 170, 51, 54, 電子情報通信学会, Jul. 2015, [Domestic magazines]
Japanese, Scientific journal

Spectro-electrochemical characterization of GaN/electrolyte interface and its application to the nanostructure formation
Yusuke Kumazaki, Akio Watanabe, Zenji Yatabe, Taketomo Sato
IEICE technical report. Electron devices, 115, 63, 63, 66, 電子情報通信学会, May 2015, [Domestic magazines]
Japanese, Scientific journal

Interface trap states in Al2O3/AlGaN/GaN structure induced by inductively coupled plasma etching of AlGaN surfaces
Zenji Yatabe, Joel T. Asubar, Taketomo Sato, Tamotsu Hashizume
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, 212, 5, 1075, 1080, May 2015, [Peer-reviewed]
English, Scientific journal

Formation of GaN-Porous Structures Using Photo-Assisted Electrochemical Process in Back-Side Illumination Mode
Akio Watanabe, Yusuke Kumazaki, Zenji Yatabe, Taketomo Sato
ECS ELECTROCHEMISTRY LETTERS, 4, 5, H11, H13, 2015, [Peer-reviewed]
English, Scientific journal

Bias-dependent photoabsorption properties of gan porous structures under back-side illumination
Taketomo Sato, Hirofumi Kida, Yusuke Kumazaki, Zenji Yatabe
ECS Transactions, 69, 2, 161, 166, Electrochemical Society Inc., 2015, [Peer-reviewed]
English, International conference proceedings

Characterization of electronic states at insulator/(Al)GaN interfaces for improved insulated gate and surface passivation structures of GaN-based transistors
Zenji Yatabe, Yujin Hori, Wan-Cheng Ma, Joel T. Asubar, Masamichi Akazawa, Taketomo Sato, Tamotsu Hashizume
Japanese Journal of Applied Physics, 53, 10, 100213-1, 10, Institute of Physics, Oct. 2014, [Peer-reviewed]
English, Scientific journal, <b>38^th JSAP Paper Award</b>



<b>Spotlights 2014</b>



<b>Selected Topics in Applied Physics, "Progresses and Future Prospects in Nitride Semiconductors"</b>



This paper presents a systematic characterization of electronic states at insulators/(Al)GaN interfaces, particularly focusing on insulator/AlGaN/GaN structures. First, we review important results reported for GaN metal–insulator–semiconductor (MIS) structures. SiO₂ is an attractive material for MIS transistor applications due to its large bandgap and high chemical stability. In-situ SiNx is effective for improving the operation stability of high electron mobility transistors (HEMTs). Meanwhile, Al₂O₃/GaN structures have high band offsets and low interface state densities, which are also desirable for insulated gate applications. We have proposed a calculation method for describing capacitance–voltage (<i>C</i>–<i>V</i>) characteristics of HEMT MIS structures for evaluating electronic state properties at the insulator/AlGaN interfaces. To evaluate near-midgap states at insulator/AlGaN interfaces, a photo-assisted <i>C</i>–<i>V</i> technique using photon energies less than the bandgap of GaN has been developed. Using the calculation in conjunction with the photo-assisted <i>C</i>–<i>V</i> technique, we estimate interface state density distributions at the Al₂O₃/AlGaN interfaces.

Correlation between Structural and Photoelectrochemical Properties of GaN Porous Nanostructures Formed by Photo-Assisted Electrochemical Etching
Yusuke Kumazaki, Akio Watanabe, Zenji Yatabe, Taketomo Sato
Journal of The Electrochemical Society, 161, 10, 705, 709, The Electrochemical Society, Aug. 2014, [Peer-reviewed]
English, Scientific journal, We investigated the correlation between structural and photoelectrochemical properties of GaN porous nanostructures formed by photo-assisted electrochemical etching. The porous nanostructures were formed during light irradiation of the top-surface of homo-epitaxial layers grown on freestanding GaN substrates. The pore depth, wall thickness, and surface morphology of porous nanostructures were strongly influenced by the way holes generated by the light irradiation were supplied. Such structural features influenced the optical properties of GaN porous nanostructures. The photoluminescence peaks measured on GaN porous nanostructures were shifted to higher energies because of the quantum confinement in the thin GaN walls between pores. Formation of porous nanostructure decreased the photoreflectance of the GaN surface, and the smallest reflectance was obtained from the porous sample having large pores on its surface after the ultrathin layer with small pores had been removed by surface-etching. The photoelectrochemical response measured on GaN porous nanostructures in a NaCl electrolyte were drastically enhanced by the unique features of those structures, such as low photoreflectance and large surface area. The largest photocurrents were obtained from the sample from which H₃PO₄ treatment had removed the ultrathin layer without thinning the pore walls.

III‐V族化合物半導体多孔質構造の形成と機能素子への応用
佐藤威友, 熊崎祐介, 渡部晃生
表面技術協会講演大会講演要旨集, 129th, 295, 297, Mar. 2014, [Invited]
Japanese, Symposium

GaNパワー素子のための絶縁膜界面制御
橋詰 保, 谷田部 然治, 佐藤 威友
電気学会研究会資料. EDD, 電子デバイス研究会, EDD-14, 39-49, 13, 16, Mar. 2014, [Invited], [Domestic magazines]
Japanese

Interface Characterization and Control of GaN-based Heterostructures
HASHIZUME TAMOTSU, YATABE ZENJI, SATO TAKETOMO
表面科学, 35, 2, 96-101 (J-STAGE), 101, The Surface Science Society of Japan, 2014, [Invited]
English, Scientific journal, Interface properties of GaN-based heterostructures have been characterized. Schottky contacts on dry-etched n-GaN layers showed leaky I-V characteristics. An anneal process at 400°C was effective in recovering the rectifying characteristics. To characterize interface properties of Al₂O₃ insulated gates on AlGaN/GaN structures with and without the inductively coupled plasma (ICP) etching of AlGaN, we have developed a C-V calculation method taking into account electronic state charges at the Al₂O₃/AlGaN interface and a photoassisted C-V technique utilizing photons with energies less than the bandgap of AlGaN. It was found that the ICP etching caused the monolayer-level interface roughness, disorder of the chemical bonds and formation of various types of defect complexes at the AlGaN surface, resulting in poor C-V characteristics due to high-density interface states at the Al₂O₃/AlGaN interface.

Photoelectrode properties of GaN porous structures formed by photo-assisted electrochemical process
KUMAZAKI YUSUKE, WATANABE AKIO, YATABE ZENJI, SATO TAKETOMO
電子情報通信学会技術研究報告, 113, 329(ED2013 64-89), 113, 116, Nov. 2013
Japanese, Symposium

Investigation on optical absorption properties of electrochemically formed porous InP using photoelectric conversion devices
Yusuke Kumazaki, Tomohito Kudo, Zenji Yatabe, Taketomo Sato
Applied Surface Science, 279, 116, 120, 15 Aug. 2013, [Peer-reviewed]
English, Scientific journal

Photoabsorption and Photoelectric Conversion Properties of InP Porous Structures Formed by the Electrochemical process　　　　　　　　　　　　　　　
KUMAZAKI Yusuke, JINBO Ryohei, YATABE Zenji, SATO Taketomo
電子情報通信学会技術研究報告, 113, 39(ED2013-27), 61, 64, May 2013
Japanese, Symposium

電気化学的手法によるInP多孔質構造の光吸収特性と光電変換　　　　　　　　　　　　　　　
熊崎 祐介, 神保 亮平, 谷田部 然治, 佐藤 威友
電子情報通信学会技術研究報告, 113, 39(ED2013-27), 61, 64, May 2013
Japanese, Symposium

Formation and Photoelectrical Measurements of Pt Schottky Interfaces on InP Porous Structures
Ryohei Jinbo, Yusuke Kumazaki, Zenji Yatabe, Taketomo Sato
ECS Transactions, 50, 37, 247, 252, Mar. 2013, [Peer-reviewed]
English, International conference proceedings, Schottky interfaces were formed on InP porous structures by the electrodeposition of Pt films. The coverage of the Pt film and its optical reflectance depended largely on the surface morphology of the porous structure. Removal of the irregular top layer formed at the initial stage of the pore formation effectively improved the coverage of the Pt film inside pores. According to <i>I</i>-<i>V</i> measurements, the Pt/porous InP showed higher photocurrents with lower dark currents than those of a reference planar sample.

Control of Insulated Gate Interfaces on AlGaN/GaN Heterostructures for Power Devices
Yujin Hori, Taketomo Sato, Tamotsu Hashizume
2013 1ST IEEE WORKSHOP ON WIDE BANDGAP POWER DEVICES AND APPLICATIONS (WIPDA), 143, 146, 2013, [Peer-reviewed]
English, International conference proceedings

Large photocurrent-response observed at Pt/InP Schottky interface formed on anodic porous structure
Ryohei Jinbo, Tomohito Kudo, Zenji Yatabe, Taketomo Sato
THIN SOLID FILMS, 520, 17, 5710, 5714, Jun. 2012, [Peer-reviewed]
English, Scientific journal

Electrochemical formation of InP porous structures for their application to photoelectric conversion devices(Session 2B : Graphene and III-Vs)
OKAZAKI Hiroyuki, SATO Taketomo, HASHIZUME Tamotsu
Technical report of IEICE. SDM, 110, 110, 85, 89, The Institute of Electronics, Information and Communication Engineers, 23 Jun. 2010
English, Symposium, We report the electrochemical formation of porous structures on n-type epitaxial layers grown on p-type InP substrates in view of the application to the photoelectric conversion devices. We successfully formed the arrays of regular-sized pores whose diameter and depth could be changed by the doping density and anodic conditions, respectively. From the photo I-V measurements, we confirmed the optical absorption process in the porous layers whose photovoltaic response strongly depended on the structural properties.

Realization of an extremely low reflectance surface based on InP porous nanostructures for application to photoelectrochemical solar cells
Taketomo Sato, Naoki Yoshizawa, Tamotsu Hashizume
THIN SOLID FILMS, 518, 15, 4399, 4402, May 2010, [Peer-reviewed]
English, Scientific journal

Low Reflectance Surface Observed on InP Porous Structures after Photoelectrochemical Etching
T. Sato, N. Yoshizawa, H. Okazaki, T. Hashizume
SEMICONDUCTOR ELECTROLYTE INTERFACE AND PHOTOELECTROCHEMISTRY, 25, 42, 83, 88, 2010, [Peer-reviewed]
English, International conference proceedings

Electrochemical Functionalization of InP Porous Nanostructures with a GOD Membrane for Amperometric Glucose Sensors
Taketomo Sato, Akinori Mizohata, Tamotsu Hashizume
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 157, 2, H165, H169, 2010, [Peer-reviewed]
English, Scientific journal

Electrochemical Formation of InP Porous Structures and Their Application to High-Sensitive Chemical Sensors
SATO Taketomo, YOSHIZAWA Naoki, OKAZAKI Hiroyuki, HASHIZUME Tamotsu
電子情報通信学会技術研究報告. ED, 電子デバイス, ED2010, 35, 11, 15, The Institute of Electronics, Information and Communication Engineers, 2010
Japanese, Symposium, We proposed a novel ion-sensitive field-effect transistor (ISFET) having a porous-gate structure. Porous structures were formed in n-type InP layers, working as channel layers, grown on p-type (001) substrates. The porous-gate ISFETs could detect the potential changes at the inner pores with a current signal whose value can be controlled by the back gate bias applied to the p-type substrate. Our proposed ISFETs demonstrated good performance for detecting pH values in the electrolyte, showing promise for high-sensitive chemical sensors.

OPTICAL AND ELECTRICAL PROPERTIES OF InP POROUS STRUCTURES FORMED ON P-N SUBSTRATES
Hiroyuki Okazaki, Taketomo Sato, Naoki Yoshizawa, Tamotsu Hashizume
2010 22ND INTERNATIONAL CONFERENCE ON INDIUM PHOSPHIDE AND RELATED MATERIALS (IPRM), 2010, [Peer-reviewed]
English, International conference proceedings

Fundamental Study of InP-Based Open-Gate Field-Effect Transistors for Application to Liquid-Phase Chemical Sensors
Naoki Yoshizawa, Taketomo Sato, Tamotsu Hashizume
JAPANESE JOURNAL OF APPLIED PHYSICS, 48, 9, 91102, Sep. 2009, [Peer-reviewed]
English, Scientific journal

Report on "The 2008 Workshop for Refreshing Science in Sapporo (Hokkaido Univ.)"
ARITA Masashi, SUGAWARA Yo, UEMURA Tetsuya, ADACHI Satoshi, SUGAWARA Hirotake, KASAI Seiya, MATSUDA Ken-ichi, SATO Taketomo, TAKAHASHI Yasuo, FUKUI Takashi
応用物理教育, 33, 1, 25, 30, 31 Jul. 2009
Japanese, Symposium

Integration of Zn-Cd-Te-Se Semiconductors on Si Platforms via Structurally Designed Cubic Templates Based on Group IV Elements
John Tolle, Radek Roucka, Brandon Forrest, Andrew V. G. Chizmeshya, John Kouvetakis, Vijay R. D'Costa, Christian D. Poweleit, Michael Groenert, Taketomo Sato, Jose Menendez
CHEMISTRY OF MATERIALS, 21, 14, 3143, 3152, Jul. 2009, [Peer-reviewed]
English, Scientific journal

Formation and application of InP porous structures on p-n substrates
SATO Taketomo, YOSHIZAWA Naoki, OKAZAKI Hiroyuki, HASHIZUME Tamotsu
IEICE technical report. Electron devices, 109, 97, 117, 120, The Institute of Electronics, Information and Communication Engineers, 17 Jun. 2009
English, Symposium, We demonstrated to form InP porous structures on n-type epitaxial layers grown on p-type (001) substrates. The high-density array of straight pores with 150nm diameter and 5000nm depth was formed by the electrochemical anodization process, where the pore depth could be controlled by the anodization time in the n-type layer. The present p-n InP porous structures show the low optical reflectance in UV-, visible- and near-infrared region. The current transport properties clearly show the rectifying behavior. These features are very promising for practical application to high-efficiency photo-s...

Formation and application of InP porous structures on p-n substrates
SATO Taketomo, YOSHIZAWA Naoki, OKAZAKI Hiroyuki, HASHIZUME Tamotsu
Technical report of IEICE. SDM, 109, 98, 117, 120, The Institute of Electronics, Information and Communication Engineers, 17 Jun. 2009
English, Symposium, We demonstrated to form InP porous structures on n-type epitaxial layers grown on p-type (001) substrates. The high-density array of straight pores with 150nm diameter and 5000nm depth was formed by the electrochemical anodization process, where the pore depth could be controlled by the anodization time in the n-type layer. The present p-n InP porous structures show the low optical reflectance in UV-, visible- and near-infrared region. The current transport properties clearly show the rectifying behavior. These features are very promising for practical application to high-efficiency photo-s...

Electrochemical formation and functionalization of InP porous nanostructures and their application to chemical sensors(Session8B: High-Frequency, Photonic and Sensing Devices)
MIZOHATA Akinori, YOSHIZAWA Naoki, SATO Taketomo, HASHIZUME Tamotsu
Technical report of IEICE. SDM, 108, 122, 327, 330, The Institute of Electronics, Information and Communication Engineers, 02 Jul. 2008
English, Symposium, We investigated the electrocatalytic activity of n-type InP porous nanostructures and the feasibility of their functionalization for the biochemical sensor applications. The porous structures have extremely large surface areas over 10m^2/cm^3 and superior electrical properties with conductive semiconductor substrates. The response currents to the addition of H_2O_2 increased on the porous electrodes due to their enlarged surface area, and its sensitivity had good linearity with H_20_2 concentration. As a first attempt of the electrochemical functionalization, glucose oxidase membrane was su...

Electrochemical formation and functionalization of InP porous nanostructures and their application to chemical sensors(Session8B: High-Frequency, Photonic and Sensing Devices)
MIZOHATA Akinori, YOSHIZAWA Naoki, SATO Taketomo, HASHIZUME Tamotsu
IEICE technical report. Electron devices, 108, 121, 327, 330, The Institute of Electronics, Information and Communication Engineers, 02 Jul. 2008
English, Symposium, We investigated the electrocatalytic activity of n-type InP porous nanostructures and the feasibility of their functionalization for the biochemical sensor applications. The porous structures have extremely large surface areas over 10m^2/cm^3 and superior electrical properties with conductive semiconductor substrates. The response currents to the addition of H_2O_2 increased on the porous electrodes due to their enlarged surface area, and its sensitivity had good linearity with H_20_2 concentration. As a first attempt of the electrochemical functionalization, glucose oxidase membrane was su...

Amperometric detection of hydrogen peroxide using InP porous nanostructures
Taketomo Sato, Akinori Mizohata, Naoki Yoshizawa, Tamotsu Hashizume
APPLIED PHYSICS EXPRESS, 1, 5, 51202, May 2008, [Peer-reviewed]
English, Scientific journal

Photoelectrochemical etching and removal of the irregular top layer formed on InP porous nanostructures
Taketomo Sato, Akinori Mizohata
ELECTROCHEMICAL AND SOLID STATE LETTERS, 11, 5, H111, H113, 2008, [Peer-reviewed]
English, Scientific journal

Electrochemical formation of InP porous nanostructures and its application to amperometric chemical sensors
Taketomo Sato, Akinori Mizohata, Toshiyuki Fujino, Tamotsu Hashizume
PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 5, NO 11 2008, 5, 11, 3475, 3478, 2008, [Peer-reviewed]
English, International conference proceedings

Complete removal of irregular top layer for sensor applications of InP porous nanostructures
Taketomo Sato, Akinori Mizohata, Naoki Yoshizawa, Tamotsu Hashizume
ECS Transactions, 16, 3, 405, 410, 2008, [Peer-reviewed]
English, International conference proceedings

Electrochemical formation of InP porous nanostructures and its application to amperometric chemical sensors
Taketomo Sato, Akinori Mizohata, Toshiyuki Fujino, Tamotsu Hashizume
Physica Status Solidi (C) Current Topics in Solid State Physics, 5, 11, 3475, 3478, 2008, [Peer-reviewed]
English, International conference proceedings

Liquid-phase chemical sensors using InP-based open-gate FETs
Naoki Yoshizawa, Taketomo Sato, Akinori Mizohata
Proceedings of IEEE Sensors, 1305, 1308, 2008, [Peer-reviewed]
English, International conference proceedings

化合物半導体ナノ構造の自己組織化形成と高感度化学センサへの応用
佐藤威友
村田学術振興財団年報, 21, 222, 229, Dec. 2007
Japanese, Research society

陽極酸化によりn‐GaN上に形成された酸化膜の評価と応用
塩崎奈々子, 石川史太郎, TRAMPERT A, GRAHN H. T, 佐藤威友, 橋詰保
応用物理学会学術講演会講演予稿集, 68th, 3, 1431, 04 Sep. 2007
Japanese

Size-controlled porous nanostructures formed on InP(001) substrates by two-step electrochemical process
Toshiyuki Fujino, Taketomo Sato, Tamotsu Hashizume
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, 46, 7A, 4375, 4380, Jul. 2007, [Peer-reviewed]
English, Scientific journal

Formation of thin native oxide layer on n-GaN by electrochemical process in mixed solution with glycol and water
Nanako Shiozaki, Taketomo Sato, Tamotsu Hashizume
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, 46, 4A, 1471, 1473, Apr. 2007, [Peer-reviewed]
English, Scientific journal

Electrochemical formation of size-controlled InP nanostructures using anodic and cathodic reactions
Taketomo Sato, Toshiyuki Fujino, Tamotsu Hashizume
ELECTROCHEMICAL AND SOLID STATE LETTERS, 10, 5, H153, H155, 2007, [Peer-reviewed]
English, Scientific journal

Performance of open-gate AlGaN/GaN HFET in various kinds of liquids
KOKAWA Takuya, SATO Taketomo, HASHIZUME Tamotsu
Extended abstracts of the ... Conference on Solid State Devices and Materials, 2006, 326, 327, 13 Sep. 2006
English, International conference proceedings

Optical Properties of Size-Controlled Porous Nanostructures Formed on n-InP (001) Substrates by Electrochemical Process
FUJINO Toshiyuki, SATO Taketomo, HASHIZUME Tamotsu
Extended abstracts of the ... Conference on Solid State Devices and Materials, 2006, 728, 729, 13 Sep. 2006
English, International conference proceedings

Selective molecular beam epitaxy growth of size- and position-controlled GaN/AlGaN nanowires on nonplanar (0001) substrates and its growth mechanism
Sato Taketomo, Oikawa Takeshi, Hasegawa Hideki, Hashizume Tamotsu
Journal of Vacuum Science & Technology B Microelectronics and Nanometer Structures, 24, 4, 2087, 2092, 26 Jul. 2006, [Peer-reviewed]
English, Scientific journal, Fundamental growth properties were investigated for the size-controlled selective MBE growth of AlGaN/GaN nanowires on the GaN (0001) prepatterned substrates both experimentally and theoretically. The lateral size of the present GaN nanowire was determined by two facet boundaries formed within AlGaN barrier layers. From the series of wire growth experiments, the growth selectivity and the measured angle of the facet boundary strongly depended on the Al composition and the initial crystalline facets of the mesa patterned templates. The experimental evolution of the cross-sectional structures...

Liquid-phase sensors using open-gate AlGaN/GaN high electron mobility transistor structure
Takuya Kokawa, Taketomo Sato, Hideki Hasegawa, Tamotsu Hashizume
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, 24, 4, 1972, 1976, Jul. 2006, [Peer-reviewed]
English, Scientific journal

Future of heterostructure microelectronics and roles of materials research for its progress
Hideki Hasegawa, Seiya Kasai, Taketomo Sato, Tamotsu Hashizume
IEICE TRANSACTIONS ON ELECTRONICS, E89C, 7, 874, 882, Jul. 2006, [Peer-reviewed], [Invited]
English, Scientific journal

Future of heterostructure microelectronics and roles of materials research for its progress
Hideki Hasegawa, Seiya Kasai, Taketomo Sato, Tamotsu Hashizume
IEICE TRANSACTIONS ON ELECTRONICS, E89C, 7, 874, 882, Jul. 2006, [Peer-reviewed], [Invited]
English, Scientific journal

Selective molecular beam epitaxy growth of size- and position-controlled GaN/AlGaN nanowires on nonplanar (0001) substrates and its growth mechanism
Taketomo Sato, Takeshi Oikawa, Hideki Hasegawa, Tamotsu Hashizume
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, 24, 4, 2087, 2092, Jul. 2006, [Peer-reviewed]
English, Scientific journal

Self-assembled formation of uniform InP nanopore arrays by electrochemical anodization in HCl based electrolyte
Taketomo Sato, Toshiyuki Fujino, Hideki Hasegawa
APPLIED SURFACE SCIENCE, 252, 15, 5457, 5461, May 2006, [Peer-reviewed]
English, Scientific journal

Sensing mechanism of InP hydrogen sensors using Pt Schottky diodes formed by electrochemical process
T Kimura, H Hasegawa, T Sato, T Hashizume
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, 45, 4B, 3414, 3422, Apr. 2006, [Peer-reviewed]
English, Scientific journal

Embedded nanowire network growth and node device fabrication for GaAs-based high-density hexagonal binary decision diagram quantum circuits
T Tamura, Tamai, I, S Kasai, T Sato, H Hasegawa, T Hashizume
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, 45, 4B, 3614, 3620, Apr. 2006, [Peer-reviewed]
English, Scientific journal

Precisely controlled anodic etching for processing of GaAs-based quantum nanostructures and devices
N Shiozaki, T Sato, M Akazawa, H Hasegawa
JOURNAL DE PHYSIQUE IV, 132, 249, 253, Mar. 2006, [Peer-reviewed]
English, Scientific journal

Precisely controlled anodic etching for processing of GaAs-based quantum nanostructures and devices
N Shiozaki, T Sato, M Akazawa, H Hasegawa
JOURNAL DE PHYSIQUE IV, 132, 249, 253, Mar. 2006, [Peer-reviewed]
English, Scientific journal

Electrochemical formation of chaotic and regular nanostructures on (001) and (111)B InP substrates and their photoluminescence characterizations
Toshiyuki Fujino, Takeshi Kimura, Taketomo Sato, Hideki Hasegawa, Tamotsu Hashizume
e-Journal of Surface Science and Nanotechnology, 4, 184, 191, 10 Feb. 2006, [Peer-reviewed]
English, Scientific journal

Growth simulation and actual MBE growth of triangular GaAs nanowires on patterned (111)B substrates
Isao Tamai, Taketomo Sato, Hideki Hasegawa, Tamotsu Hashizume
e-Journal of Surface Science and Nanotechnology, 4, 19, 24, 12 Jan. 2006, [Peer-reviewed]
English, International conference proceedings

Dynamics and control of recombination process at semiconductor surfaces, interfaces and nano-structures
Hideki Hasegawa, Taketomo Sato, Seiya Kasai, Boguslawa Adamowicz, Tamotsu Hashizume
SOLAR ENERGY, 80, 6, 629, 644, 2006, [Peer-reviewed], [Invited]
English, Scientific journal

Performance of electrodeposited Pt/InP Schottky diode as a hydrogen sensing head for InP-based wireless sensor chips
Takeshi Kimura, Hideki Hasegawa, Taketomo Sato, Tamotsu Hashizume
2006 INTERNATIONAL CONFERENCE ON INDIUM PHOSPHIDE AND RELATED MATERIALS CONFERENCE PROCEEDINGS, 443, +, 2006, [Peer-reviewed]
English, International conference proceedings

Toward ultra-low power III-V quantum large scale integrated circuits for ubiquitous network era
Hasegawa Hideki, Kasai Seiya, Sato Taketomo
Frontiers in Electronics, 41, 2, 421, 436, 2006, [Peer-reviewed]

Liquid sensor using gateless AlGaN/GaN HEMT structure
KOKAWA TAKUYA, KIMURA TAKESHI, SATO TAKETOMO, KASAI SEIYA, HASEGAWA HIDEKI, HASHIZUME TAMOTSU
IEICE technical report. Electron devices, 105, 326(ED2005 139-156), 39, 42, 東京 : 電子情報通信学会, 07 Oct. 2005
Japanese

Fabrication of AlGaN/GaN nano wire network using selective RF-MBE
OIKAWA TAKESHI, SATO TAKETOMO, HASEGAWA HIDEKI, HASHIZUME TAMOTSU
IEICE technical report. Electron devices, 105, 325(ED2005 118-138), 89, 92, The Institute of Electronics, Information and Communication Engineers, 06 Oct. 2005
Japanese, Symposium, For fabrication of AlGaN/GaN quantum wire network structures, we studied feasibility of selective MBE growth of AlGaN/GaN wire structures on pre-patterned GaN(0001) substrates. A mesa stripe type pattern and a hexagonal network type pattern were prepared by ECR-RIBE dry etching. As for the mesa direction, <1-100>-direction and <11-20>-direction were compared, and <11-20>-oriented mesa was found to be suitable for the selective growth of wire structures due to larger growth selectivity of GaN/AlGaN layers. Fabricated wire network structure showed strong CL emission, originating form wire structure. For the realization of precise size control of quantum wire structure, time evolution of cross-sectional features and Al composition dependence of the growth selectivity were investigated in detail.

Embedded Nanowire Network Growth and Node Device Fabrication for GaAs-Based High-Density Hexagonal BDD Quantum Circuits
TAMAURA Takahiro, TAMAI Isao, KASAI Seiya, SATO Taketomo, HASEGAWA Hideki, HASHIZUME Tamotsu
Extended abstracts of the ... Conference on Solid State Devices and Materials, 2005, 152, 153, 13 Sep. 2005
English, International conference proceedings

Sensing Mechanism of InP Hydrogen Sensors Using Pt Schottky Diodes Formed by Electrochemical Process
KIMURA Takeshi, HASEGAWA Hideki, SATO Taketomo, HASHIZUME Tamotsu
Extended abstracts of the ... Conference on Solid State Devices and Materials, 2005, 218, 219, 13 Sep. 2005
English, International conference proceedings

Growth kinetics and theoretical modeling of selective molecular beam epitaxy for growth of GaAs nanowires on nonplanar (001) and (111)B substrates
T Sato, Tamai, I, H Hasegawa
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, 23, 4, 1706, 1713, Jul. 2005, [Peer-reviewed]
English, Scientific journal

Effects of surface states and Si-interlayer based surface passivation on GaAs quantum wires grown by selective molecular beam epitaxy
N Shiozaki, T Sato, H Hasegawa
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, 23, 4, 1714, 1721, Jul. 2005, [Peer-reviewed]
English, Scientific journal

Investigation of Side-gating Effects in GaAs-based Quantum Wire Transistor (QWRTr) utilizing Nanosized Schottky Gates
JIA Rui, KASAI Seiya, SATO Taketomo, HASEGAWA Hideki
IEICE technical report. Electron devices, 105, 110, 31, 36, The Institute of Electronics, Information and Communication Engineers, 03 Jun. 2005
English, Symposium, Side-gating effects inhibiting the high-density integration of devices GaAs-based quantum wire transistors (QWRTrs) with nanosized Schottky gates controlling etched nanowires were investigated experimentally. Side-gating behaviors depended on the distance between the side-gate and nanowire edge d_<sg>, and when d_<sg><500nm and nanowire mesa etching was shallow, the large side-gating effect occurred, which could not be explained by the electrostatic effect. At the same time, anomalously large side-gate leakage current due to electron tunneling was observed. Here, we propose a model for the ...

Surface Passivation Using a Si Interface Control Layer for AlGaAs/GaAs Quantum Srctures Fabricated on GaAs(111)B Substrates
AKAZAWA MASAMICHI, AKAZAWA MASAMICHI, SHIOZAKI NANAKO, SHIOZAKI NANAKO, SATO TAKETOMO, SATO TAKETOMO, HASEGAWA HIDEKI, HASEGAWA HIDEKI
電子情報通信学会技術研究報告, 105, 110(ED2005 58-66), 25, 30, The Institute of Electronics, Information and Communication Engineers, 03 Jun. 2005
Japanese, Symposium, We attempted to apply a Si-interface-control-layer (Si ICL)-based surface passivation method to the surfaces of quantum structures fabricated on GaAs(111)B substrates. The sample surfaces were investigated by an XPS study at each step of the fabrication process, and fabricated quantum structures were characterized by PL measurements. Shifts of surface Fermi level positions toward the conduction band edges at GaAs and AlGaAs(111)B surfaces were observed after the Si ICL formation. PL intensities reduced with reduction of distances between quantum structures and their surfaces. The surface passivation using the Si-ICL, however, recovered PL intensities for quantum structures.

Study on ECR dry etching and selective MBE growth of AlGaN/GaN for fabrication of quantum nanostructures on GaN (0001) substrates
T Oikawa, F Ishikawa, T Sato, T Hashizume, H Hasegawa
APPLIED SURFACE SCIENCE, 244, 1-4, 84, 87, May 2005, [Peer-reviewed]
English, Scientific journal

Electrochemical processes for formation, processing and gate control of III-V semiconductor nanostructures
H Hasegawa, T Sato
ELECTROCHIMICA ACTA, 50, 15, 3015, 3027, May 2005, [Peer-reviewed], [Invited]
English, Scientific journal

Surface-related reduction of photoluminescence in GaAs quantum wires and its recovery by new passivation
N Shiozaki, S Anantathanasarn, T Sato, T Hashizume, H Hasegawa
APPLIED SURFACE SCIENCE, 244, 1-4, 71, 74, May 2005, [Peer-reviewed]
English, Scientific journal

Electrochemical processes for formation, processing and gate control of III-V semiconductor nanostructures
H Hasegawa, T Sato
ELECTROCHIMICA ACTA, 50, 15, 3015, 3027, May 2005, [Peer-reviewed]
English, Scientific journal

Growth of AlGaN/GaN quantum wire structures by radio-frequency-radical-assisted selective molecular beam epitaxy on prepatterned substrates
T Sato, T Oikawa, H Hasegawa
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, 44, 4B, 2487, 2491, Apr. 2005, [Peer-reviewed]
English, Scientific journal

Cross-sectional evolution and its mechanism during selective molecular beam epitaxy growth of GaAs quantum wires on (111)B substrates
Tamai, I, T Sato, H Hasegawa
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, 44, 4B, 2652, 2656, Apr. 2005, [Peer-reviewed]
English, Scientific journal

量子細線ネットワークと論理回路応用
長谷川英機, 葛西誠也, 佐藤威友
応用物理, 74, 3, 320, 326, Mar. 2005, [Peer-reviewed], [Invited]
Japanese, Scientific journal

Fabrication and Characterization of GaAs BDD Quantum Node Devices Utilized Selective MBE Growth Technique
TAMURA TAKAHIRO, YUMOTO MIKI, TAMAI ISAO, KASAI SEIYA, SATO TAKETOMO, HASEGAWA HIDEKI
電子情報通信学会技術研究報告, 104, 624(SDM2004 222-228), 19, 24, The Institute of Electronics, Information and Communication Engineers, 20 Jan. 2005
Japanese, Symposium, For realization of future quantum-LSIs (Q-LSIs) based on the novel hexagonal binary decision diagram (BDD) circuit approach, quantum wire (QWR) switches and BDD node devices utilizing selectively MBE grown (SG) QWR networks were investigated. Fabricated SG QWR switches using <-110> and <510>-directed nanowires on GaAs (001) substrate operated as conventional FETs at low temperature up to room temperature and clear conductance quantization was observed at low temperature. Their gate control characteristics were studied by gate-dependent Shubnikov-de-Haas oscillation measurements and it was confirmed good gate controllability of SG QWR switches controlled by Shottky wrap gates (WPGs). Y-branch BDD node devices were successfully fabricated combining <-110> and <510>-directed QWRs and realized clear path-switching. Their speed and power performances were also estimated and values of switching speed τ=50ps and PDP=10^<-18>J were obtained.

Selective MBE growth of shape-, size-, and position- controlled GaAs nanowire networks on (111)B patterned substrates　　　　　　　　　　　　　　　
Isao Tamai, Taketomo Sato, Hideki Hasegawa
2005 International Semiconductor Device Research Symposium, 2005, 350, 351, 2005
English, International conference proceedings

Selective MBE growth of high-density hexagonal nanowire networks on pre-patterned GaAs (001) and (111)B substrates　　　　　　　　　　　　　　　
Isao Tamai, Taketomo Sato, Hideki Hasegawa
Proceedings - Electrochemical Society, PV 2004-13, 71, 86, 2005
English, International conference proceedings

Design and implementation of ultra-small-size and ultra-low-power digital systems on GaAs-based hexagonal nanowire networks utilizing a hexagonal BDD quantum circuit approach　　　　　　　　　　　　　　　
S. Kasai, M. Yumoto, T. Sato, H. Hasegawa
Proceedings - Electrochemical Society, PV 2004-13, 125, 146, 2005
English, International conference proceedings

Fabrication of AlGaN/GaN nano wire network using selective RF-MBE　　　　　　　　　　　　　　　
OIKAWA TAKESHI, SATO TAKETOMO, HASEGAWA HIDEKI, HASHIZUME TAMOTSU
電子情報通信学会技術研究報告，CPM, CPM2005, 134, 89, 92, 2005
Japanese, Symposium

Electrodeposited Pt/InP Schottky barriers with large barrier heights and large hydrogen sensitivity for sensor chips using InP-Based uanturn wire networks
T Kimura, T Sato, T Hashizume, H Hasegawa
2005 International Conference on Indium Phosphide and Related Materials, 533, 536, 2005
English, International conference proceedings

ゲートレス型AlGaN/GaN -HEMTを利用した溶液センサ
KOKAWA TAKUYA, KIMURA TAKESHI, SATO TAKETOMO, KASAI SEIYA, HASEGAWA HIDEKI, HASHIZUME TAMOTSU
電子情報通信学会技術研究報告，CPM, CPM2005, 134, 39, 42, The Institute of Electronics, Information and Communication Engineers, 2005
Japanese, Symposium, Liquid phase chemical sensors using gateless Al_<0.24>Ga_<0.76>N/GaN HEMT structure were fabricated, and their sensing performances including pH responses were investigated. The device was covered with a SiO_2 film except an open gate window which was exposed to various liquid solutions. Sensing characteristics were measured in a standard electrochmical cell with a potentiostat and a saturated caromel reference electrode, and the latter provided gate control of the device. The devices exhibited I-V characteristics similar to those of conventional HEMTs in various solutions, showing tight gate control and complete pinch off. The drain current in the linear region changed linearly with pH value of the solution, giving a surface potential variation rate of 50.4mV/pH value of the solution, giving a surface potential variation rate of 50.4mV/pH which is close to the Nernstian value. The diode also indicated feasibility of sensing of polarizable liquids through potential shift by dipoles.

Hexagonal binary decision diagram quantum circuit approach for ultra-low power III-V quantum LSIs
H Hasegawa, S Kasai, T Sato
IEICE TRANSACTIONS ON ELECTRONICS, E87C, 11, 1757, 1768, Nov. 2004, [Peer-reviewed], [Invited]
English, Scientific journal

Growth of AlGaN/GaN Quantum Wire Structures by RF-Radical Assisted Selective MBE on Pre-Patterned Substrates
SATO Taketomo, OIKAWA Takeshi, HASHIZUME Tamotsu, HASEGAWA Hideki
Extended abstracts of the ... Conference on Solid State Devices and Materials, 2004, 814, 815, 15 Sep. 2004
English, International conference proceedings

Cross-Sectional Evolution and Its Mechanism during Selective MBE Growth of GaAs Quantum Wires on (111)B Substrates
TAMAI Isao, SATO Taketomo, HASEGAWA Hideki
Extended abstracts of the ... Conference on Solid State Devices and Materials, 2004, 880, 881, 15 Sep. 2004
English, International conference proceedings

Evolution mechanism of heterointerface cross-section during growth of GaAs ridge quantum wires by selective molecular beam epitaxy
T Sato, Tamai, I, S Yoshida, H Hasegawa
APPLIED SURFACE SCIENCE, 234, 1-4, 11, 15, Jul. 2004, [Peer-reviewed]
English, Scientific journal

Growth kinetics and modeling of selective molecular beam epitaxial growth of GaAs ridge quantum wires on pre-patterned nonplanar substrates
T Sato, Tamai, I, H Hasegawa
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, 22, 4, 2266, 2274, Jul. 2004, [Peer-reviewed]
English, Scientific journal

Selective molecular beam epitaxy growth of GaAs hexagonal nanowire networks on (111)B patterned substrates
S Yoshida, Tamai, I, T Sato, H Hasegawa
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 43, 4B, 2064, 2068, Apr. 2004, [Peer-reviewed]
English, Scientific journal

内部交差量子細線構造の深さ分解/面内分布カソードルミネッセンス評価
石川史太郎, 及川武, 玉井功, 佐藤威友, 長谷川英機
応用物理学関係連合講演会講演予稿集, 51st, 3, 1540, 28 Mar. 2004
Japanese

Formation of high-density GaAs hexagonal nano-wire networks by selective MBE growth on pre-patterned (001) substrates
Tamai, I, T Sato, H Hasegawa
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 21, 2-4, 521, 526, Mar. 2004, [Peer-reviewed]
English, Scientific journal

Formation of high-density GaAs hexagonal nano-wire networks by selective MBE growth on pre-patterned (001) substrates
Tamai, I, T Sato, H Hasegawa
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 21, 2-4, 521, 526, Mar. 2004, [Peer-reviewed]
English, Scientific journal

Fabrication and Characterization of Quantum Wire Switch for Hexagonal BDD Quantum Integrated Circuits
YUMOTO MIKI, TAMURA TAKAHIRO, SATO TAKETOMO, HASEGAWA HIDEKI
電子情報通信学会技術研究報告, 103, 631(SDM2003 213-221), 15, 19, The Institute of Electronics, Information and Communication Engineers, 30 Jan. 2004
Japanese, Symposium, In view of applications to hexagonal binary decision diagram (BDD) LSIs, a first attempt is made to form quantum BDD node switches on selectively grown (SG) embedded quantum wires (QWRs) by molecular beam epitaxy (MBE). SG QWR branch switches controlled by Schottky wrap gate (WPG) were successfully fabricated by MBE growth and subsequent device processing. Gate control characteristics were studied by gate-dependent Shubnikov-de-Haas measurements, and the behavior was found to be similar to that of devices fabricated on wires by etching. The switch exhibited clear conductance quantization at low temperature, and temperature dependence of the voltage slope of conductance jump was clarified. A Y-branch BDD node device using two SG branch switches was successfully fabricated, and they realized clear path switching characteristics.

Formation of GaAs Quantum Wire Networks on (111)B patterned substrates using MBE Selective Growth
YOSHIDA SOICHI, TAMAI ISAO, SATO TAKETOMO, HASEGAWA HIDEKI
電子情報通信学会技術研究報告, 103, 630(SDM2003 207-212), 23, 28, The Institute of Electronics, Information and Communication Engineers, 29 Jan. 2004
Japanese, In view of applications to hexagonal BDD diagram quantum circuits, the growth of hexagonal GaAs nanowire networks was attempted by MBE selective growth. The basic feasibility of <112>-oriented straight nanowires was first investigated. GaAs nanowires were selectively formed on the top of (111)B plane of AlGaAs mesa structures with high uniformity. The wire width was controlled by the growth conditions. Then, GaAs hexagonal networks were grown on patterned substrates. The results of detailing structural and optical studies showed that highly uniform and smoothly connected hexagonal networks were successfully fabricated by selective MBE growth technique.

Fabrication of BDD quantum node switches on embedded GaAs quantum wires grown by selective MBE
M Yumoto, T Tamura, T Sato, H Hasegawa
SUPERLATTICES AND MICROSTRUCTURES, 34, 3-6, 485, 491, Sep. 2003, [Peer-reviewed]
English, Scientific journal

Selective MBE Growth of Hexagonal Nano-wire Networks on GaAs Patterned Substrates
SATO TAKETOMO, TAMAI ISAO, YOSHIDA SOICHI, HASEGAWA HIDEKI
電子情報通信学会技術研究報告, 103, 117(ED2003 50-57), 29, 34, The Institute of Electronics, Information and Communication Engineers, 13 Jun. 2003
Japanese, Symposium, Attempts were made to grow GaAs ridge nano-wires and hexagonal GaAs nanowire networks by selective MBE growth on (001) and (111)B pre-patterned substrates. Growth on mesa stripes produced embedded GaAs ridge quantum wires (QWRs) on the top of AlGaAs ridge structures. From the detail investigation on growth process, the size of GaAs ridge wires was geometrically determined by the difference of growth rate on two kinds of crystal facets of ridge structures, where the wire size can be kinetically controlled by growth conditions and initial pattern size. Uniform hexagonal nano-wire networks were successfully fabricated on hexagonal patterned substrates by combining <-110>- and two <510>-wire directions for (001) substrates and on hexagonal patterned substrates by combining three <-1-12> wire directions for (111)B substrates.

Selective MBE Growth of GaAs Ridge Quantum Wires for Formation of Hexagonal Nanowire Networks.
SATO TAKETOMO, TAMAI ISAO, YOSHIDA SOICHI, HASEGAWA HIDEKI
電子情報通信学会技術研究報告, 102, 640(SDM2002 244-251), 27, 32, The Institute of Electronics, Information and Communication Engineers, 10 Feb. 2003
Japanese, Symposium, Attempts were made to grow GaAs ridge nano-wires and hexagonal GaAs nanowire networks by selective MBE growth on (001) pre-pattemed substrates.<-110>-and<510>-oriented mesa stripes produced embedded GaAs ridge quantum wires (QWRs) on the top of AlGaAs ridge structures. From the detail investigation on growth process, the size of GaAs ridge wires was geometrically determined by the difference of growth rate on two kinds of crystal facets of ridge structures, where the wire size can be kinetically controlled by growth conditions and initial pattern size. Based on underlying growth mechanism, uniform hexagonal nano-wire networks were successfully fabricated on hexagonal patterned substrates by combining<-110>-and<510>-wire directions.

Effects of surface states on control characteristics of nano-meter scale Schottky gates formed on GaAs
A Kameda, S Kasai, T Sato, H Hasegawa
SOLID-STATE ELECTRONICS, 47, 2, 323, 331, Feb. 2003, [Peer-reviewed]
English, Scientific journal

Selective MBE growth of GaAs ridge quantum wire arrays on patterned (001) substrates and its growth mechanism
T Sato, Tamai, I, H Hasegawa
COMPOUND SEMICONDUCTORS 2002, 174, 3, 145, 148, 2003, [Peer-reviewed]
English, Scientific journal

Prospects of III-V quantum LSIs based on hexagonal BDD approach
Seiya Kasai, Taketomo Sato, Hideki Hasegawa
2003 International Semiconductor Device Research Symposium, ISDRS 2003 - Proceedings, 482, 483, Institute of Electrical and Electronics Engineers Inc., 2003, [Peer-reviewed]
English, International conference proceedings

Electrochemical formation of self-assembled InP nanopore arrays and their use as templates for molecular beam epitaxy growth of InGaAs quantum wires and dots
T Hirano, A Ito, T Sato, F Ishikawa, H Hasegawa
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 41, 2B, 977, 981, Feb. 2002, [Peer-reviewed]
English, Scientific journal

Fabrication of GaAs/AlGaAs Quantum Wires and Quantum Network Structures using MBE selective growth.
TAMAI ISAO, SATO TAKETOMO, HASEGAWA HIDEKI
電子情報通信学会技術研究報告, 101, 617(ED2001 224-231), 15, 20, 28 Jan. 2002
Japanese, Symposium

Fabrication of porous InP structure by Electrochemical Process and itsApplication.
HIRANO TETSURO, SATO TAKETOMO, HASEGAWA HIDEKI
電子情報通信学会技術研究報告, 101, 617(ED2001 224-231), 49, 54, 28 Jan. 2002
Japanese, Symposium

MBE選択成長法によるGaAs/AlGaAs量子細線の形成とその結合ネットワークへの応用　　　　　　　　　　　　　　　
TAMAI ISAO, SATO TAKETOMO, HASEGAWA HIDEKI
電子情報通信学会研究会技術研究報告, ED2001, 101/617, 15, 20, 2002
Japanese, Symposium

Selective MBE growth of GaAs/AlGaAs nanowires on patterned GaAs (001) substrates and its application to hexagonal nanowire network formation
T Sato, Tamai, I, C Jiang, H Hasegawa
COMPOUND SEMICONDUCTORS 2001, 170, 170, 325, 330, 2002, [Peer-reviewed]
English, Scientific journal

Selective MBE Growth of <-110>- and <510>- Oriented GaAs Ridge Quantum Wires on Patterned (001) Substrates for Formation of Hexagonal Nanowire Networks　　　　　　　　　　　　　　　
Sato Taketomo, Tamai Isao, Jiang Chao, Hasegawa Hideki
The Second International Workshop on Quantum Nonplanar Nanostructures & Nanoelectronics, 283, 286, 2002
English, International conference proceedings

電気化学的手法によるInPポーラス構造の形成と応用　　　　　　　　　　　　　　　
HIRANO Tetsuro, SATO Taketomo, HASEGAWA Hideki
電子情報通信学会研究会技術研究報告, ED2001, 101-617/, 49, 54, 2002
Japanese, Symposium

電気化学プロセスによるInPポーラス構造の形成とその応用(2)
平野哲郎, 佐藤威友, 伊藤章, 石川史太郎, 長谷川英機
応用物理学会学術講演会講演予稿集, 62nd, 3, 1059, 11 Sep. 2001
Japanese

Current transport and capacitance-voltage characteristics of GaAs and InP nanometer-sized Schottky contacts formed by in situ electrochemical process
T Sato, S Kasai, H Hasegawa
APPLIED SURFACE SCIENCE, 175, 181, 186, May 2001, [Peer-reviewed]
English, Scientific journal

電気化学プロセスによるInPポーラス構造の形成とその応用
平野哲郎, 佐藤威友, 伊藤章, 石川史太郎, 長谷川英機
応用物理学関係連合講演会講演予稿集, 48th, 3, 1378, 28 Mar. 2001
Japanese

Electrical properties of nanometer-sized Schottky contacts for gate control of III-V single electron devices and quantum devices
T Sato, S Kasai, H Hasegawa
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 40, 3B, 2021, 2025, Mar. 2001, [Peer-reviewed]
English, Scientific journal

Electrical properties of nanometer-sized Schottky contacts for gate control of III-V single electron devices and quantum devices
T Sato, S Kasai, H Hasegawa
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 40, 3B, 2021, 2025, Mar. 2001, [Peer-reviewed]
English, Scientific journal

Effects of surface fermi level pinning and surface state charging on control characteristics of nanometer scale Schottky gates formed on GaAs
A Kameda, S Kasai, T Sato, H Hasegawa
2001 INTERNATIONAL SEMICONDUCTOR DEVICE RESEARCH SYMPOSIUM, PROCEEDINGS, 626, 629, 2001
English, International conference proceedings

Electrochemical formation of self-assembled nanopore arrays as templates for MBE growth of InP-based quantum wires and dots
T Hirano, A Ito, T Sato, F Ishikawa, H Hasegawa
2001 INTERNATIONAL CONFERENCE ON INDIUM PHOSPHIDE AND RELATED MATERIALS, CONFERENCE PROCEEDINGS, 378, 381, 2001
English, International conference proceedings

Unpinning of Fermi level in nanometer-sized Schottky contacts on GaAs and InP
H Hasegawa, T Sato, S Kasai
APPLIED SURFACE SCIENCE, 166, 1-4, 92, 96, Oct. 2000, [Peer-reviewed]
English, Scientific journal

Electrical properties of nanometer-sized Schottky contacts on n-GaAs and n-InP formed by in situ electrochemical process
T Sato, S Kasai, H Okada, H Hasegawa
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, 39, 7B, 4609, 4615, Jul. 2000, [Peer-reviewed]
English, Scientific journal

Electrochemical formation of uniform and straight nano-pore arrays on (001) InP surfaces and their photoluminescence characterizations
H Fujikura, AM Liu, A Hamamatsu, T Sato, H Hasegawa
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 39, 7B, 4616, 4620, Jul. 2000, [Peer-reviewed]
English, Scientific journal

Electrical Characterization on Nano-Schottky Contacts Fabricated Using the Electrochemical Process.
SATO TAKETOMO, KASAI SEIYA, OKADA HIROSHI, HASEGAWA HIDEKI
電子情報通信学会技術研究報告, 99, 616(ED99 306-318), 79, 84, The Institute of Electronics, Information and Communication Engineers, 10 Feb. 2000
Japanese, The current transport characteristics of nanometer-sized Schottky contacts were investigated from theoretical and experimental viewpoints. A theoretical calculation of the 3D potential distributions has shown that the potential shape underneath the nano-Schottky contacts is greatly modified by the surface Fermi level pinning on the air exposed free surfaces. This leads to non-linear log I-V characteristics which are different from a standard thermionic emission characteristics obtained on the macro-Schottky contacts. On the other hand, the Pt nano-particles were selectively formed using the in situ electrochemical process, their I-V measurements were made using an conductive AFM system. The log I-V curves of the nano-Schottky contacts showed non-linear characteristics and could be very well explained by the theoretical I-V curves considering the "environmental" Fermi level pinning.

Self-assembled formation of InP nanopore arrays by electrochemical anodization
H Fujikura, AM Liu, T Sato, T Hirano, H Hasegawa
2000 INTERNATIONAL CONFERENCE ON INDIUM PHOSPHIDE AND RELATED MATERIALS, CONFERENCE PROCEEDINGS, 510, 513, 2000, [Peer-reviewed]
English, International conference proceedings

Properties of nanometer-sized metal-semiconductor interfaces of GaAs and InP formed by an in situ electrochemical process
H Hasegawa, T Sato, C Kaneshiro
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, 17, 4, 1856, 1866, Jul. 1999, [Peer-reviewed]
English, Scientific journal

Fabrication of Nano-Schottky Contacts on Compound Semiconductor by Pulsed Mode Electrochemical Process and Its Characterization.
SATO TAKETOMO, OKADA HIROSHI, HASEGAWA HIDEKI
電子情報通信学会技術研究報告, 99, 21(ED99 1-10), 39, 44, The Institute of Electronics, Information and Communication Engineers, 22 Apr. 1999
Japanese, Symposium, Nanometer-sized Schottky contacts were successfully formed on InP and related materials by combining an in situ electrochemical process and a standard electron beam (EB) lithography. At the initial stage of the optimized electrochemical process, uniform Pt particles with diameter of 26 nm were formed in a self-assembled fashion on unmasked n-InP subdtrates, and this led to a highest Schottky barrier heights (SBHs) of 0.86 eV Under this optimized condition, a mushroom type Pt gate could be formed on EB patterned n-InAlAs substrates. Furthermore, regular arrays of Pt dot with a diameter of 30nm were selectively fabricated Within open circular windows. l-V characteridtics measured using a conductive atomic force microscopy (AFM) tip indicated that a single Pt dot formed a wel1-behaved nanometer Schottky contact.

Formation of size- and position-controlled nanometer size Pt dots on GaAs and InP substrates by pulsed electrochemical deposition
T Sato, C Kaneshiro, H Okada, H Hasegawa
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 38, 4B, 2448, 2452, Apr. 1999, [Peer-reviewed]
English, Scientific journal

The strong correlation between interface microstructure and barrier height in Pt/n-InP Schottky contacts formed by an in situ electrochemical process
T Sato, C Kaneshiro, H Hasegawa
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 38, 2B, 1103, 1106, Feb. 1999, [Peer-reviewed]
English, Scientific journal

Electrochemical etching of indium phosphide surfaces studied by voltammetry and scanned probe microscopes
C Kaneshiro, T Sato, H Hasegawa
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 38, 2B, 1147, 1152, Feb. 1999, [Peer-reviewed]
English, Scientific journal

Formation of nanometer-sized Schottky contacts on InP and related materials by in situ electrochemical process　　　　　　　　　　　　　　　
Taketomo Sato, Hiroshi Okada, Hideki Hasegawa
Conference Proceedings - International Conference on Indium Phosphide and Related Materials, 233, 236, IEEE, 1999
English, Scientific journal

Realization of strongly metal-dependent Schottky barrier heights on n-GaAs by in situ electrochemical process
C Kaneshiro, T Sato, H Hasegawa
COMPOUND SEMICONDUCTORS 1998, 162, 585, 590, 1999, [Peer-reviewed]
English, Scientific journal

GaAs-based single electron logic and memory devices using electrodeposited nanometer Schottky gates
Hiroshi Okada, Taketomo Sato, Kei-ichiroh Jinushi, Hideki Hasegawa
Microelectronic Engineering, 47, 1-4, 285, 287, 1999

Formation of Size- and Position-Controlled Nanometer Size Pt Dots on GaAs and InP Substrates by Pulsed Electrochemical Deposition
SATO Taketomo, KANESHIRO Chinami, OKADA Hiroshi, HASEGAWA Hideki
Extended abstracts of the ... Conference on Solid State Devices and Materials, 1998, 74, 75, 07 Sep. 1998
English

Formation and control of Schottky contacts on compound semiconductors by in situ electrochemical process.
KANESHIRO CHINAMI, SATO TAKETOMO, KOYAMA YUJI, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
電子情報通信学会技術研究報告, 98, 185(ED98 84-97), 55, 60, The Institute of Electronics, Information and Communication Engineers, 22 Jul. 1998
Japanese, Symposium, Well-controlled Schottky contacts were successfully formed on compound semiconductors, such as GaAs, Inp and GaN, by an in situ electrochemical process. The fabricated diodes showed nearly ideal thermionic emission transport characteristics. In the initial stage of metal deposition, metal particles with a size of 20-30nm were formed on semiconductor surfaces. This process can realize oxide-, defect-, and stress-free metal-semiconductor interfaces, and Schottky barrier heights were found to be strongly dependent on metal workfunction.

Fabrication of the Metal dot array by Electrochemical Process.
SATO TAKETOMO, KANESHIRO CHINAMI, OKADA HIROSHI, HASEGAWA HIDEKI
電子情報通信学会技術研究報告, 98, 184(ED98 76-83), 21, 26, The Institute of Electronics, Information and Communication Engineers, 21 Jul. 1998
Japanese, Symposium, Pt dot arrays were formed on n-GaAs by combining the electrochemical process with the electron-beam(EB) lithoghography. In order to define dot positions, dot-array windows were patterned on GaAs by EB lithography. It is possible to form the metal particles on only the opened areas of EB patterned substrates, thereby realizing precise dot-positions control. In this study, Pt particles with a diameter of 20nm could be formed in the center of each naked GaAs surface patterned with a period of 200nm. In the measurements by the AFM system with conductive probes, I-V characteristics of each Pt dots/n-GaAs contact showed rectifying behavior due to Schottky barrier formation.

Strong correlation between interface microstructure and barrier height in N-InP Schottky contacts formed by in situ electrochemical process
T Sato, C Kaneshiro, H Hasegawa
1998 INTERNATIONAL CONFERENCE ON INDIUM PHOSPHIDE AND RELATED MATERIALS - CONFERENCE PROCEEDINGS, 623, 626, 1998, [Peer-reviewed]
English, International conference proceedings

Highly controllable electrochemical etching of InP studied by voltammetry and scanned probe microscope
C Kaneshiro, T Sato, H Hasegawa
1998 INTERNATIONAL CONFERENCE ON INDIUM PHOSPHIDE AND RELATED MATERIALS - CONFERENCE PROCEEDINGS, 191, 194, 1998, [Peer-reviewed]
English, International conference proceedings

Electrochemical formation and characterization of Schottky in-plane and wrap gate structures for realization of GaAs- and InP-based quantum wires and dots
H Hasegawa, T Sato, H Okada, K Jinushi, S Kasai, Y Satoh
APPLIED SURFACE SCIENCE, 123, 335, 338, Jan. 1998, [Peer-reviewed]
English, Scientific journal

Control of Schottky Barrier Heights on Indium Phosphite-Based Materials by In-Situ Electrochemical Process and Its Mechanism.
SATO TAKETOMO, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
電子情報通信学会技術研究報告, 97, 158(ED97 65-74), 13, 18, The Institute of Electronics, Information and Communication Engineers, 14 Jul. 1997
Japanese, Symposium, Well-controlled Schottky barriers were successfully formed on InP-based materials by a novel in-situ electrochemical process. The Pt contacts by this process realized oxide-, defect- and stress-free Schottky interfaces, resulting in substantially increased Schottky barrier heights (SBHs) of 0.86eV, 0.50eV and 0.89eV for n-InP, n-InAlAs and n-InGaAs, respectively. The mechanism of the SBH enhancement was explained by the disorder induced gap state (DIGS) model.

Evolution mechanism of nearly pinning-free platinum/n-type indium phosphide interface with a high Schottky barrier height by in situ electrochemical process
H Hasegawa, T Sato, T Hashizume
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, 15, 4, 1227, 1235, Jul. 1997, [Peer-reviewed]
English, Scientific journal

Large Schottky barrier heights on indium phosphide-based materials realized by in-situ electrochemical process
T Sato, S Uno, T Hashizume, H Hasegawa
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 36, 3B, 1811, 1817, Mar. 1997, [Peer-reviewed]
English, Scientific journal

Formation of pinning-free Schottky barriers on InP and related materials by novel in-situ electrochemical process and its mechanism
T Sato, H Hasegawa
1997 INTERNATIONAL CONFERENCE ON INDIUM PHOSPHIDE AND RELATED MATERIALS - CONFERENCE PROCEEDINGS, 517, 520, 1997, [Peer-reviewed]
English, International conference proceedings

High Schottky Barrier Formation on Indium Phosphide-Based Materials by In-Situ Electrochemical Process.
SATO TAKETOMO, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
電子情報通信学会技術研究報告, 96, 352(ED96 112-119), 9, 15, The Institute of Electronics, Information and Communication Engineers, 08 Nov. 1996
Japanese, Symposium, Pt Schottky barriers were formed on InP-based materials by a novel in-situ electrochemical process. The electrical characteristics, surfaces and interfaces of the Schottky diodes were investigated by I-V, C-V, DLTS and AFM measurements. The Schottky Barrier heights (SBHs) formed by this electrochemical process were much higher than those formed by the electron-beam (EB) deposition process. The mechanism for increase of SBH was explained by the disorder induced gap state (DIGS) model.

Enhancement of Schottky Barrier Heights on Indium Phosphide-Based Materials by In-Situ Electrochemical Process and Its Mechanism
SATO Taketomo, UNO Shouichi, HASHIZUME Tamotsu, HASEGAWA Hideki
Extended abstracts of the ... Conference on Solid State Devices and Materials, 1996, 106, 108, 26 Aug. 1996
English, International conference proceedings

Fabrication of high-performance InP MESFETs with in-situ pulse-plated metal gates
S Uno, T Hashizume, T Sato, H Hasegawa
1996 EIGHTH INTERNATIONAL CONFERENCE ON INDIUM PHOSPHIDE AND RELATED MATERIALS, 338, 341, 1996, [Peer-reviewed]
English, International conference proceedings

n型GaN基板上に形成されたp型GaN層に対する低損傷光電気化学エッチングとその電気化学的評価
佐藤 威友, 電子情報通信学会技術研究報告, 123, 28, 31, 2023

窒化物半導体の光電気化学エッチングと電子デバイス応用—Photo-electrochemical Etching of Nitride Semiconductors and Electron Device Applications—電子デバイス/半導体電力変換合同研究会・パワーデバイス・パワーエレクトロニクスとその実装技術
佐藤 威友, 電気学会研究会資料. SPC = The papers of technical meeting on semiconductor power converter, IEE Japan / 半導体電力変換研究会 [編], 2022, 172-177・179-190, 61, 64, 01 Dec. 2022
電気学会, Japanese

窒化物半導体の光電気化学エッチングと電子デバイス応用—Photo-electrochemical Etching of Nitride Semiconductors and Electron Device Applications—電子デバイス/半導体電力変換合同研究会 パワーデバイス・パワーエレクトロニクスとその実装技術
佐藤 威友, 電気学会研究会資料. EDD = The papers of technical meeting on electron devices, IEE Japan / 電子デバイス研究会 [編], 2022, 32-37・39-50, 61, 64, 01 Dec. 2022
電気学会, Japanese

Photo-electrochemical Etching of Nitride Semiconductors and Electron Device Applications
佐藤威友, 電気学会研究会資料(Web), EDD-22-032-037.039-050/SPC-22-172-177.179-190, 2022

電気化学反応を利用した窒化ガリウムのウェットエッチングと機能性材料
佐藤 威友, 信学技報 IEICE Technical Report, 122, 25, 28, 2022

Fabrication of porous gallium nitride (GaN) utilizing two-step etching method and control of its optical properties
SATO Taketomo, TOGUCHI Masachika, Denki Kagaku, 89, 4, 365, 369, 05 Dec. 2021
The Electrochemical Society of Japan, Japanese

Fabrication of recessed-gate AlGaN/GaN HEMTs utilizing contactless photoelectrochemical (CL-PEC) etching (2)
渡久地政周, 三輪和希, 堀切文正, 福原昇, 成田好伸, 市川磨, 磯野僚多, 田中丈士, 佐藤威友, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 68th, 2021

Fabrication of recessed-gate AlGaN/GaN HEMTs utilizing contactless photoelectrochemical (CL-PEC) etching
渡久地政周, 三輪和希, 堀切文正, 福原昇, 成田好伸, 市川磨, 磯野僚多, 田中丈士, 佐藤威友, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 67th, 2020

Wet Etching of III-V Compound Semiconductors – Focusing a Recent Topics on Nitride Semiconductors –
Sato Taketomo, Toguchi Masachika, JSAP Annual Meetings Extended Abstracts, 2019.2, 169, 169, 04 Sep. 2019
The Japan Society of Applied Physics, Japanese

Introductory Talk
Sato Taketomo, JSAP Annual Meetings Extended Abstracts, 2019.2, 194, 194, 04 Sep. 2019
The Japan Society of Applied Physics, Japanese

電気化学堆積法によるCu₂O/InPヘテロ界面の形成(3)
近江沙也夏, 熊崎祐介, 佐藤威友, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 64th, 2017

光電気化学反応を利用したn-GaN表面ダメージ層の除去
枝元将彰, 松本悟, 熊崎祐介, 佐藤威友, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 64th, 2017

GaN多孔質構造の形状およびキャリア濃度の違いとインピーダンス特性について
伊藤圭亮, ZHANG Xiaoyi, 熊崎祐介, 佐藤威友, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 64th, 2017

光電気化学反応を利用したGaN表面の陽極酸化
枝元将彰, 熊崎祐介, 佐藤威友, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 63rd, 2016

金属有機化合物分解法によるGaN表面へのNiO粒子の形成
喜田弘文, 伊藤圭亮, 熊崎祐介, 佐藤威友, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 63rd, 2016

異方性ウェットエッチングによるGaN多孔質構造の作製と光学特性評価
熊崎祐介, 松本悟, 佐藤威友, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 63rd, 2016

電気化学堆積法によるCu₂O/InPヘテロ界面の形成
近江沙也夏, 熊崎祐介, 佐藤威友, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 63rd, 2016

電気化学堆積法によるCu₂O/GaNヘテロ構造の形成と特性評価
熊崎祐介, 近江沙也夏, 谷田部然治, 佐藤威友, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 62nd, 2015

ドライエッチングがAl₂O₃/AlGaN/GaN構造のMOS界面特性に与える影響
谷田部然治, 谷田部然治, 大平城二, 佐藤威友, 橋詰保, 橋詰保, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 62nd, 2015

電気化学的手法によるⅢ-Ⅴ族半導体多孔質構造の形成と高感度化学センサへの応用
佐藤 威友, 渡部 晃生, 熊崎 祐介, Proceedings of the Chemical Sensor Symposium, 56, 64, 66, Mar. 2014
電気化学会化学センサ研究会, Japanese

AlGaN/GaNヘテロ構造上に形成したp-GaN層の選択的電気化学エッチング
熊崎祐介, 佐藤威友, 橋詰保, 橋詰保, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 61st, 2014

窒化物半導体異種接合の評価と制御
佐藤威友, 赤澤正道, 橋詰保, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 61st, 2014

電気化学的手法によるGaN多孔質構造の形成と光学特性の評価
熊崎祐介, 渡部晃生, 神保亮平, 谷田部然治, 佐藤威友, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 60th, 2013

pn接合基板に形成したInP多孔質構造の光応答特性
工藤 智人, 佐藤 威友, 応用物理学会学術講演会講演予稿集, 2011.2, 2571, 2571, 16 Aug. 2011
公益社団法人 応用物理学会, Japanese

多孔質構造を有するイオン感応性電界効果トランジスタ
佐藤 威友, 岡崎 拓行, 応用物理学会学術講演会講演予稿集, 2010.2, 3681, 3681, 30 Aug. 2010
公益社団法人 応用物理学会, Japanese

InP多孔質構造の光吸収特性と光電変換
佐藤 威友, 岡崎 拓行, 応用物理学会学術講演会講演予稿集, 2010.2, 3008, 3008, 30 Aug. 2010
公益社団法人 応用物理学会, Japanese

電気化学的手法によるInP多孔質構造の形成と孔壁表面の機能化
岡崎 拓行, 佐藤 威友, 応用物理学会学術講演会講演予稿集, 2010.2, 2843, 2843, 30 Aug. 2010
公益社団法人 応用物理学会, Japanese

Electrochemical formation and sensor application of InP porous nanostructures
SATO Taketomo, FUJINO Toshiyuki, HASHIZUME Tamotsu, IEICE technical report, 107, 110, 269, 272, 18 Jun. 2007
A two-step electrochemical process was developed to form high-density array of InP porous nanostructures. By the subsequent cathodic decomposition after the porous formation, the thickness of InP pore walls was precisely controlled in the nanometer-scale range from 30 to 15 nm, resulted in formation of the unique nanostructures with a high aspect ratio. The current response of the porous samples to a hydrogen peroxide (H_2O_2) was increased due to the large surface area, as compared with the planar InP substrate. The results indicate that the present nanostructures is promising for the application to bio-chemical sensors., The Institute of Electronics, Information and Communication Engineers, English

Control of defect and impurity states at AlGaN surfaces for sensor application
HASHIZUME T., KANEKO M., KOTANI J., KOKAWA T., KIMURA T., SATO T., IEICE technical report, 106, 137, 93, 98, 26 Jun. 2006
We proposed a surface control process for suppressing tunneling leakage currents of Schottky contacts on AlGaN/GaN heterostrcutures. The process consisted of the nitrogen radical treatment, the deposition of an ultrathin Al layer, the UHV annealing and finally the removal of the Al layer. The Ni/Au Schottky gates fabricated on the processed AlGaN surfaces showed pronounced reduction of leakage current and clear temperature dependence of I-V curves. The H_2 gas-sensing characteristics of Pd Schottky diodes formed on AlGaN/GaN heterostructure were investigated. The Pd/AlGaN/GaN diode showed the systematic shift in the C-V curve for different partial pressure of H_2, keeping the shape of the curve approximately the same. The maximum shift in the threshold voltage obtained was about 1200mV which is much larger than 500mV reported for the Pd-based Si MOS sensors. Liquid-phase sensing characteristics of open-gate AlGaN/GaN HEMT structures were investigated in aqueous solutions. We observed a fine parallel shift in the transfer curves according to change in pH value in a solution, indicating the corresponding potential change at the AlGaN surface. The sensitivity for the potential change was 57.5mV/pH., The Institute of Electronics, Information and Communication Engineers, English

半導体製造におけるウェット／ドライエッチング　　　　　　　　　　　　　　　
株)ISTL 礒部, 服部コンサルティングインターナショナル 服部, 毅, グロスバーグ合同会社, 大山, 聡, 式田 光宏, アドヒージョン(株, 河合 晃, サムコ(株, 中野 博彦, サムコ(株, 扇谷 浩通, 浜口, 智志, 豊田 紀章, 唐橋 一浩, 江利口 浩二, 寒川, 誠二, 株, 日立製作所, 篠田 和典, 佐藤 威友, 有馬, 健太, 第４章第３節GaNの光電気化学（PEC）エッチング
(株)R&D支援センター, Oct. 2022, 9784905507611, [Contributor]

Lateral Alignment of Epitaxial Quantum Dots　　　　　　　　　　　　　　　
HASEGAWA Hideki, SATO Taketomo, KASAI Seiya, 24 Large-Scale Integration of Quantum Dot Devices on MBE-Based Quantum Wire Networks
Springer, 2007, [Contributor]

Insulated gate structures for GaN-based devices using mist-CVD method　　　　　　　　　　　　　　　
谷田部然治, RADZUAN Hadirah, 尾藤圭悟, 福光将也, 中村有水, 越智亮太, 佐藤威友
電気学会研究会資料(Web), 2024
2024 - 2024

Mist Chemical Vapor Deposited Gate Dielectrics for GaN-Based MOS Device　　　　　　　　　　　　　　　
谷田部然治, 福光将也, 大竹浩史, 平倉拓海, RADZUAN Hadirah, 越智亮太, 中村有水, 佐藤威友
電子情報通信学会技術研究報告(Web), 2024
2024 - 2024

Impact of interface formation process on properties of photoelectrochemically etched p-GaN MOS interfaces　　　　　　　　　　　　　　　
JIAO Yining, 忽滑谷崇秀, 高津海, 佐藤威友, 赤澤正道
応用物理学会春季学術講演会講演予稿集(CD-ROM), 2024
2024 - 2024

Study on mask materials for GaN nanowire fabrication using contactless PEC etching　　　　　　　　　　　　　　　
古内久大, 古内久大, 本久順一, 本久順一, 佐藤威友, 佐藤威友
応用物理学会春季学術講演会講演予稿集(CD-ROM), 2024
2024 - 2024

Characterization of Mist-Al₂O₃/n-GaN Structures Fabricated on Free-standing GaN Substrates　　　　　　　　　　　　　　　
谷田部然治, 福光将也, RADZUAN Hadirah, 尾藤圭悟, 越智亮太, 中村有水, 佐藤威友
応用物理学会春季学術講演会講演予稿集(CD-ROM), 2024
2024 - 2024

Effect of UVA light on GaN nanowire fabrication using contactless PEC etching　　　　　　　　　　　　　　　
古内久大, 古内久大, 本久順一, 本久順一, 佐藤威友
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 2024
2024 - 2024

Investigation of Charge Generated at Surface of p-type GaN　　　　　　　　　　　　　　　
JIAO Y., 高橋尚伸, 島崎喬大, 佐藤威友, 赤澤正道
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 2024
2024 - 2024

Self-terminating photo-electrochemical (PEC) etching for recessed-gate fabrication on AlGaN/GaN HEMTs　　　　　　　　　　　　　　　
Takuya Togashi, Kosaku Ito, Taketomo Sato
2022 International Conference on Solid State Devices and Materials (SSDM 2022), English, Oral presentation
26 Sep. 2022 - 29 Sep. 2022

Mgドープp-GaNを用いたMOS構造のC-V特性に対する光電気化学エッチングの効果　　　　　　　　　　　　　　　
忽滑谷 崇秀, 玉村 祐也, 久保 広大, 佐藤 威友, 赤澤 正道
第83回応用物理学会秋季学術講演会, Japanese, Poster presentation
20 Sep. 2022 - 23 Sep. 2022

光電気化学(PEC)エッチングの自己停止とAlGaN/GaN HEMTのゲートリセス加工　　　　　　　　　　　　　　　
富樫 拓也, 伊藤 滉朔, 越智 亮太, 佐藤 威友
第83回応用物理学会秋季学術講演会, Japanese, Poster presentation
20 Sep. 2022 - 23 Sep. 2022

n型及びp型GaN表面の電気化学的評価　　　　　　　　　　　　　　　
高津 海, 久保 広太, 佐藤 威友
第83回応用物理学会秋季学術講演会, Japanese, Poster presentation
20 Sep. 2022 - 23 Sep. 2022

n-GaN加工表面に対するコンタクトレス光電気化学(CL-PEC)エッチング (2)　　　　　　　　　　　　　　　
大澤 由斗, 大神 洸貴, 越智 亮太, 堀切 文正, 福原 昇, 佐藤 威友
第83回応用物理学会秋季学術講演会, Japanese, Poster presentation
20 Sep. 2022 - 23 Sep. 2022

Effect of parallel conduction on the current linearity of AlGaN/GaN MIS-HEMTs　　　　　　　　　　　　　　　
Ryota Ochi, Tamotsu Hashizume, Taketomo Sato
14th Topical Workshop on Heterostructure Microelectronics (TWHM2022), English, Oral presentation
29 Aug. 2022 - 01 Sep. 2022

Contactless-Photoelectrochemical (CL-PEC) etching on process-damaged n-GaN surface　　　　　　　　　　　　　　　
Yoshito Osawa, Hiroki Ogami, Masachika Toguchi, Fumimasa Horikiri, Noboru Fukuhara, Taketomo Sato
14th Topical Workshop on Heterostructure Microelectronics (TWHM2022), English, Oral presentation
29 Aug. 2022 - 01 Sep. 2022

電気化学反応を利用した窒化ガリウムのウェットエッチングと機能性材料　　　　　　　　　　　　　　　
佐藤威友, 渡久地 政周
電子情報通信学会電子デバイス研究会, Japanese, Oral presentation
27 May 2022

n-GaN加工損傷面に対するコンタクトレス光電気化学（CL-PEC）エッチング　　　　　　　　　　　　　　　
大神洸貴, 大澤由斗, 渡久地政周, 堀切文正, 福原昇, 佐藤威友
第69回応用物理学会春季学術講演会, Japanese
22 Mar. 2022 - 26 Mar. 2022

AlGaN/GaN MIS-HEMTsにおけるパラレル伝導評価　　　　　　　　　　　　　　　
越智亮太, 橋詰保, 佐藤 威友
第69回応用物理学会春季学術講演会, Oral presentation
22 Mar. 2022 - 26 Mar. 2022

Fabrication of Recessed-gate AlGaN/GaN HEMTs by Low-Damage Contactless Photo-Electrochemical Etching　　　　　　　　　　　　　　　
M. Toguchi, K. Miwa, F. Horikiri, N. Fukuhara, Y. Narita, O. Ichikawa, R. Isono, T. Tanaka, T. Sato
4th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials, English, Invited oral presentation
06 Mar. 2022 - 10 Mar. 2022, [Invited]

低損傷コンタクトレス光電気化学エッチングを利用したリセスゲーAlGaN/GaN HEMTsの作製　　　　　　　　　　　　　　　
渡久地 政周, 三輪 和希, 堀切 文正, 福原 昇, 成田 好伸, 市川 磨, 磯野 僚多, 田中 丈士, 佐藤 威友
電子情報通信学会電子デバイス研究会, Japanese, Oral presentation
25 Nov. 2021 - 26 Nov. 2021

光電気化学エッチング法を用いたAlGaInN/AlGaN HFETの作製　　　　　　　　　　　　　　　
伊藤 滉朔, 小松裕斗, 渡久地 政周, 井上暁喜, 田中さくら, 三好実人, 佐藤 威友
電子情報通信学会電子デバイス研究会, Japanese, Oral presentation
25 Nov. 2021 - 26 Nov. 2021

HfSiOx-gate AlGaN/GaN MOS HEMTs with improved operation stability　　　　　　　　　　　　　　　
R. Ochi, T. Nabatame, T. Hashizume, T. Sato
2021 International Conference on Solid State Devices and Materials, English, Oral presentation
06 Sep. 2021 - 09 Sep. 2021

光電気化学エッチング法を用いたAlGaInN/AlGaNリセスゲートHFETの作製　　　　　　　　　　　　　　　
伊藤滉朔, 小松裕斗, 渡久地政周, 井上暁喜, 三好実人, 佐藤威友
第68回応用物理学会春季学術講演会, Japanese, Oral presentation
16 Mar. 2021 - 19 Mar. 2021

コンタクトレス光電気化学エッチングによるリセスゲートAlGaN/GaN HEMT の作製　　　　　　　　　　　　　　　
渡久地政周, 三輪和希, 堀切文正, 福原昇, 成田好伸, 吉田丈洋, 佐藤威友
第68回応用物理学会春季学術講演会, Japanese, Oral presentation
16 Mar. 2021 - 19 Mar. 2021

Precise control in threshold voltage of AlGaN/GaN HEMTs utilizing a photoelectrochemical (PEC) etching　　　　　　　　　　　　　　　
T. Sato, M. Toguchi, K. Itoh, T. Hashizume
The 8th Asian Conference on Crystal Growth and Crystal Technology (CGCT-8), English
01 Mar. 2021 - 03 Mar. 2021

Recessed-gate AlGaN/GaN HEMTs fabricated by photo-electrochemical (PEC) etching　　　　　　　　　　　　　　　
T. Sato, T. Hashizume
Virtual Workshop on Materials Science and Advanced Electronics Created by Singularity, English, Oral presentation
01 Feb. 2021 - 03 Feb. 2021

Cathode-electrode on photoelectrochemical (PEC) etching for n-GaN on n+GaN substrate　　　　　　　　　　　　　　　
福原昇, 堀切文正, 渡久地政周, 三輪和希, 大神洸貴, 佐藤威友
応用物理学会春季学術講演会講演予稿集(CD-ROM), 2021
2021 - 2021

半導体ナノ構造を利用した高感度化学センサの開発（依頼講演）　　　　　　　　　　　　　　　
佐藤威友
第6回北海道大学部局横断シンポジウム, 19 Oct. 2020, Japanese, Public symposium
[Invited]

Fabrication of Recessed-Gate AlGaN/GaN HEMTs Utilizing Contactless Photo-Electrochemical (CLPEC) Etching　　　　　　　　　　　　　　　
M. Toguchi, K. Miwa, F. Horikiri, N. Fukuhara, Y. Narita, O. Ichikawa, R. Isono, T. Tanaka, T. Sato
2020 Pacific Rim Meeting on Electrochemical and Solid State Science (PRiME 2020), English, Oral presentation
04 Oct. 2020 - 09 Oct. 2020

Photo-Electrochemical Etching and Porosification of III-Nitride Semiconductors (Invited)　　　　　　　　　　　　　　　
T. Sato, M. Toguchi
2020 Pacific Rim Meeting on Electrochemical and Solid State Science (PRiME 2020), English, Invited oral presentation
04 Oct. 2020 - 09 Oct. 2020, [Invited]

GaN Wet Etching Process for HEMT Devices (invited)　　　　　　　　　　　　　　　
F. Horikiri, N. Fukuhara, M. Toguchi, T. Sato
International symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials, English, Invited oral presentation
08 Mar. 2020 - 11 Mar. 2020, [Invited]

Characterization of ICP-RIE-processed n-GaN surface using an electrochemical method　　　　　　　　　　　　　　　
武田健太郎, 山田真嗣, 山田真嗣, 渡久地政周, 加地徹, 佐藤威友
応用物理学会春季学術講演会講演予稿集(CD-ROM), 2020
2020 - 2020

Thermal assisted contactless photoelectrochemical (PEC) etching for GaN　　　　　　　　　　　　　　　
堀切文正, 福原昇, 太田博, 浅井直美, 成田好伸, 吉田丈洋, 三島友義, 渡久地政周, 三輪和希, 大神洸貴, 佐藤威友
応用物理学会春季学術講演会講演予稿集(CD-ROM), 2020
2020 - 2020

Thermal-assisted generation of sulfate radicals for contactless photo electrochemical (PEC) etching of n-GaN　　　　　　　　　　　　　　　
三輪和希, 大神洸貴, 渡久地政周, 堀切文正, 福原昇, 成田好伸, 吉田丈洋, 佐藤威友
応用物理学会春季学術講演会講演予稿集(CD-ROM), 2020
2020 - 2020

電気めっき法によるGaNへのPt電極の形成と電気特性評価　　　　　　　　　　　　　　　
小原康, 島内道人, 佐藤威友, 本久順一
応用物理学会北海道支部/日本光学会北海道支部合同学術講演会講演予稿集, 2020
2020 - 2020

Simple Photoelectrochemical Etching for Recess Gate GaN HEMT　　　　　　　　　　　　　　　
堀切文正, 福原昇, 渡久地政周, 三輪和希, 成田好伸, 市川磨, 磯野僚多, 田中丈士, 佐藤威友
電子情報通信学会技術研究報告, 2020
2020 - 2020

Simple Photoelectrochemical Etching of GaN for RF Application　　　　　　　　　　　　　　　
F. Horikiri, N. Fukuhara, Y. Narita, T. Yoshida, M. Toguchi, K. Miwa, T. Sato
Materials Research Meeting 2019, English
10 Dec. 2019 - 14 Dec. 2019

Contactless Photoelectrochemical Etching of n-GaN in K2S2O8 solution　　　　　　　　　　　　　　　
M. Toguchi, K. Miwa, F. Horikiri, N. Fukuhara, Y. Narita, T. Yoshida, T. Sato
Materials Research Meeting 2019, English, Poster presentation
10 Dec. 2019 - 14 Dec. 2019

Precise Control in Threshold Voltage of AlGaN/GaN HEMTs by Photoelectrochemical Etching　　　　　　　　　　　　　　　
Y. Komatsu, M. Toguchi, T. Sato
Materials Research Meeting 2019, English, Poster presentation
10 Dec. 2019 - 14 Dec. 2019

Fabrication of GaN nanowires by wet processes using electrodeless photo-assisted electro- chemical etching and alkaline solution treatment　　　　　　　　　　　　　　　
M. Shimauchi, K. Miwa, M. Toguchi, T. Sato, J. Motohisa
The 9th Asia-Pacific Workshop on Widegap Semiconductors, English, Poster presentation
10 Nov. 2019 - 15 Nov. 2019

Evaluation of Radical Production Rate from S2O82- ions for GaN Etching　　　　　　　　　　　　　　　
M. Toguchi, K. Miwa, F. Horikiri, N. Fukuhara, Y. Narita, T. Yoshida, T. Sato
The 9th Asia-Pacific Workshop on Widegap Semiconductors, English, Poster presentation
10 Nov. 2019 - 15 Nov. 2019

Simple Photoelectrochemical Etching for GaN HEMT Application　　　　　　　　　　　　　　　
F. Horikiri, N. Fukuhara, Y. Narita, T. Yoshida, M. Toguchi, K. Miwa, T. Sato
The 9th Asia-Pacific Workshop on Widegap SemiconductorsThe 9th Asia-Pacific Workshop on Widegap Semiconductors, English, Poster presentation
10 Nov. 2019 - 15 Nov. 2019

Precise control in recessed-gate etching for AlGaN/GaN HEMTs by utilizing photo- electrochemical reactions　　　　　　　　　　　　　　　
Y. Komatsu, M. Toguchi, T. Sato
The 9th Asia-Pacific Workshop on Widegap Semiconductors, English, Poster presentation
10 Nov. 2019 - 15 Nov. 2019

Wet Etching of III-V Compound Semiconductors – Focusing a Recent Topics on Nitride Semiconductors –　　　　　　　　　　　　　　　
Taketomo Sato, Masachika Toguchi
2019 第80回 応用物理学会 秋季学術講演会, 18 Sep. 2019, Japanese, Invited oral presentation
[Invited], [Domestic Conference]

Fabrication GaN nanowires by electrodeless photo-assisted electrochemical etching and wet etching　　　　　　　　　　　　　　　
Michihito Shimauchi, Kazuki Miwa, Masachika Toguchi, Taketomo Sato, Junichi Motohisa
2019 第80回 応用物理学会 秋季学術講演会, 18 Sep. 2019, Japanese, Oral presentation
[Domestic Conference]

Study on photo-electrochemical etching on high-doped n-type GaN substrates　　　　　　　　　　　　　　　
Kazuki Miwa, Masachika Toguchi, Taketomo Sato
2019 第80回 応用物理学会 秋季学術講演会, 18 Sep. 2019, Japanese, Poster presentation
[Domestic Conference]

Photo-electrochemical (PEC) etching on AlGaInN/AlGaN heterostructures (2)　　　　　　　　　　　　　　　
Y. Komatsu, M. Toguchi, S. Saito, M. Miyoshi, T. Sato
2019 第80回 応用物理学会 秋季学術講演会, 18 Sep. 2019, Japanese, Poster presentation
[Domestic Conference]

Contactless Photoelectrochemical Etching of n-GaN in K2S2O8/H3PO4 Mixed Solution　　　　　　　　　　　　　　　
M. Toguchi, K. Miwa, F. Horikiri, N. Fukuhara, Y. Narita, T. Yoshida, T. Sato
2019 第80回 応用物理学会 秋季学術講演会, 18 Sep. 2019, Japanese, Oral presentation
[Domestic Conference]

Characterization of processed n-GaN surface using an electrochemical impedance spectroscopy (2)　　　　　　　　　　　　　　　
Kentaro Takeda, Masachika Toguchi, Taketomo Sato
2019 第80回 応用物理学会 秋季学術講演会, 18 Sep. 2019, Japanese, Poster presentation
[Domestic Conference]

GaN Wet Etching Process for Power and RF Devices　　　　　　　　　　　　　　　
F. Horikiri, N. Fukuhara, H. Ohta, N. Asai, Y. Narita, T. Yoshida, T. Mishima, M. Toguchi, K. Miwa, T. Sato
2019 International Conference on Solid State Devices and Materials, 05 Sep. 2019, English, Invited oral presentation
[Invited], [International presentation]

Characterization of processing-damage induced on n-GaN surface utilizing electrochemical methods　　　　　　　　　　　　　　　
Kentaro Takeda, Masachika Toguchi, Taketomo Sato
13th Topical Workshop on Heterostructure Microelectronics, 26 Aug. 2019, English, Poster presentation
[International presentation]

Photo-electrochemical etching optimized for high-doped n-type GaN　　　　　　　　　　　　　　　
Kazuki Miwa, Masachika Toguchi, Taketomo Sato
13th Topical Workshop on Heterostructure Microelectronics, 26 Aug. 2019, English, Poster presentation
[International presentation]

GaN Wet Etching Process　　　　　　　　　　　　　　　
Fumimasa Horikiri, Noboru Fukuhara, Hiroshi Ohta, Naomi Asai, Yoshinobu Narita, Takehiro Yoshida, Tomoyoshi Mishima, Masachika Toguchi, Kazuki Miwa, Taketomo Sato
13th Topical Workshop on Heterostructure Microelectronics, 26 Aug. 2019, English, Invited oral presentation
[Invited], [International presentation]

窒化物半導体の電気化学エッチングとデバイス応用（招待講演）　　　　　　　　　　　　　　　
日本表面真空学会 関西支部 合同セミナー２０１９, 05 Jul. 2019, Japanese, Invited oral presentation
[Invited]

GaN Wet Etching Process for Power and RF Devices　　　　　　　　　　　　　　　
Fumimasa Horikiri, Noboru Fukuhara, Hiroshi Ohta, Naomi Asai, Yoshinobu Narita, Takehiro Yoshida, Tomoyoshi Mishima, Masachika Toguchi, Kazuki Miwa, Taketomo Sato
2019 Asia-Pacific Workshop on Fundamentals and Applications of Advanced Semiconductor Devices, 01 Jul. 2019, English, Invited oral presentation
[Invited], [International presentation]

Damage-less Wet Etching for Normally-off AlGaN/GaN HEMTs using Photo-electrochemical Reactions　　　　　　　　　　　　　　　
Taketomo Sato, Keisuke Uemura, Masachika Toguchi
2019 International Conference on Compound Semiconductor Manufacturing Technology, 01 May 2019, English, Invited oral presentation
Minneapolis, USA, [Invited], [International presentation]

Electrochemical characterization of etching damage induced to n-GaN surface　　　　　　　　　　　　　　　
K. Takeda, M. Toguchi, T. Sato
11th International Symposium on Advanced Plasma Science and its Applications for Nitride and Nanomaterials, Mar. 2019, English, Oral presentation
[International presentation]

Low-damage wet etching for AlGaN/GaN recessed-gate HEMTs using photo-electrochemical reactions　　　　　　　　　　　　　　　
K. Uemura, Y. Komatsu, T. Sato
11th International Symposium on Advanced Plasma Science and its Applications for Nitride and Nanomaterials, Mar. 2019, English, Oral presentation
[International presentation]

光電気化学エッチングによる窒化ガリウムの微細加工の検討　　　　　　　　　　　　　　　
島内道人, 三輪和希, 渡久地政周, 佐藤威友, 本久順一
第66回応用物理学会春季学術講演会, Mar. 2019, Japanese, Oral presentation
[Domestic Conference]

AlGaInN/AlGaNヘテロ構造の光電気化学エッチング　　　　　　　　　　　　　　　
小松祐斗, 植村圭佑, 佐藤威友
第66回応用物理学会春季学術講演会, Mar. 2019, Japanese, Oral presentation
[Domestic Conference]

ペルオキソ二硫酸イオン(S2O82-)含有電解液におけるGaNの電気化学特性　　　　　　　　　　　　　　　
渡久地政周, 三輪和希, 堀切文正, 福原昇, 成田好伸, 吉田丈洋, 佐藤威友
第66回応用物理学会春季学術講演会, Mar. 2019, Japanese, Oral presentation
[Domestic Conference]

GaNの光電気化学（PEC）エッチングが有する可能性②コンタクトレスでのエッチング　　　　　　　　　　　　　　　
堀切文正, 福原昇, 太田博, 浅井直美, 成田好伸, 吉田丈洋, 三島友義, 渡久地政周, 三輪和希, 佐藤威友
第66回応用物理学会春季学術講演会, Mar. 2019, Japanese, Oral presentation
東京工業大学大岡山キャンパス，東京都目黒区, [Domestic Conference]

Effect of Photo-electrochemical Etching and Post-metallization Annealing on Gate-controllability of AlGaN/GaN High Electron Mobility Transistors　　　　　　　　　　　　　　　
K. Uemura, M. Deki, Y. Honda, H. Amano, T. Sato
International Workshop on Nitride Semiconductors 2018 (IWN2018), Nov. 2018, English, Oral presentation
[International presentation]

Low-damage Etching for GaN-based Electronic Devices utilizing Photo-electrochemical Reactions　　　　　　　　　　　　　　　
SATO Taketomo
4th Intensive Discussion on Growht of Nitride Semiconductors, Nov. 2018, English, Invited oral presentation
[Invited], [International presentation]

Fabrication of GaN Porous Nanostructures utilizing Electrochemical Reactions　　　　　　　　　　　　　　　
T. Sato
HU-SNU Joint Symposium, Nov. 2018, English, Oral presentation
[International presentation]

Precise thickness control in recess-etching for normally-off AlGaN/GaN HEMTs using a photo-electrochemical reaction　　　　　　　　　　　　　　　
K. Uemura, Y. Komatsu, T. Sato
HU-SNU Joint Symposium, Nov. 2018, English, Poster presentation
[International presentation]

Electrochemical Formation and Application of Porous Gallium Nitride　　　　　　　　　　　　　　　
T. Sato, M. Toguchi
Americas International Meeting on Electrochemistry and Solid State Science (AiMES 2018), Oct. 2018, English, Invited oral presentation
[Invited], [International presentation]

AlGaN/GaNヘテロ構造トランジスタを基盤とする高感度化学センサの検討
小松祐斗, 植村圭佑, 渡久地政周, 佐藤威友
電気化学秋季大会講演要旨集(CD‐ROM), 11 Sep. 2018, Japanese

窒化ガリウム加工基板に対する選択的光電気化学エッチングの検討
渡久地政周, 武田健太郎, 佐藤威友
電気化学秋季大会講演要旨集(CD‐ROM), 11 Sep. 2018, Japanese

電気化学インピーダンス法を用いたn‐GaN加工表面の評価
武田健太郎, 渡久地政周, 佐藤威友
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 05 Sep. 2018, Japanese

Recessed-gate AlGaN/GaN High Electron Mobility Transistors (HEMTs) Prepared by Photo-electrochemical Etching and Post-metallization Annealing　　　　　　　　　　　　　　　
K. Uemura, M. Deki, Y. Honda, H. Amano, T. Sato
第79 回応用物理学会秋季大会、19p-CE-4（日韓ジョイントシンポジウム, Sep. 2018, English, Oral presentation
[International presentation]

Control of Pore Depth in GaN Porous Structures Utilizing a Photoabsorption Process Under below-Bandgap Illumination　　　　　　　　　　　　　　　
M. Toguchi, S. Matsumoto, T. Sato
233rd ECS Meeting, May 2018, English, Poster presentation
[International presentation]

Precisely-controlled etching of gallium nitride utilizing electrochemical reactions　　　　　　　　　　　　　　　
T. Sato, M. Toguchi
Nanotech Malaysia 2018, May 2018, English, Invited oral presentation
[Invited], [International presentation]

表面加工を施した窒化ガリウムの特異的光吸収特性と光電気化学エッチングの制御
渡久地政周, 佐藤威友
電気化学会大会講演要旨集(CD-ROM), 23 Feb. 2018, Japanese

光電気化学反応を利用した窒化物半導体の低損傷エッチングと電子デバイスへの応用　　　　　　　　　　　　　　　
植村圭佑, 松本悟, 渡久地政周, 伊藤圭亮, 佐藤 威友
電子情報通信学会 電子デバイス研究会, Dec. 2017, Japanese, Oral presentation
[Domestic Conference]

Improved wet-etching processes for GaN-based electron devices　　　　　　　　　　　　　　　
T. Sato, K. Uemura, T. Hashizume
2017 MRS Fall Meeting and Exhibit, Nov. 2017, English, Invited oral presentation
[Invited], [International presentation]

Photo-electrochemical Formation of Porous Nanostructures on n-type GaN utilizing Franz-Keldysh Effect　　　　　　　　　　　　　　　
M. Toguchi, S. Matsumoto, T. Sato
The 8th International Symposium on Surface Science (ISSS8), Oct. 2017, English, Poster presentation
[International presentation]

Removal of reactive-ion-etching damage from n-GaN surface using a photoelectrochemical process　　　　　　　　　　　　　　　
S. Matsumoto, M. Toguchi, T. Sato
2017 International Conference on Solid State Devices and Materials (SSDM 2017), Sep. 2017, English, Oral presentation
[International presentation]

Franz‐Keldysh効果を用いた窒化ガリウムの光電気化学反応制御
渡久地政周, 佐藤威友
電気化学秋季大会講演要旨集(CD‐ROM), 28 Aug. 2017, Japanese

光電気化学反応を利用したn‐GaN表面層の低損傷エッチング
松本悟, 佐藤威友, 成田哲生, 成田哲生, 加地徹, 橋詰保, 橋詰保
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 25 Aug. 2017, Japanese

光電気化学(PEC)反応を利用したリセスゲートAlGaN/GaN HEMTの作製
植村圭佑, 佐藤威友, 橋詰保
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 25 Aug. 2017, Japanese

Highly-controllable etching for AlGaN/GaN recessed-gate structures utilizing low-damage electrochemical reactions　　　　　　　　　　　　　　　
K. Uemura, Y. Kumazaki, T. Sato, T. Hashizume
12th Topical Workshop on Heterostructure Microelectronics (TWHM 2017), Aug. 2017, English, Poster presentation
[International presentation]

Precise thickness control in recess-etching for normally-off AlGaN/GaN HEMTs using a low damage photo-electrochemical reaction　　　　　　　　　　　　　　　
T. Sato, K. Uemura, Y. Kumazaki, T. Hashizume
12th International Conference on Nitride Semiconductors (ICNS 12), Jul. 2017, Japanese, Poster presentation
[International presentation]

2段階異方性エッチングによる窒化ガリウム多孔質構造の形成と形状制御
佐藤威友, 熊崎祐介, 松本悟
電気化学会大会講演要旨集(CD-ROM), 17 Mar. 2017, Japanese

GaN多孔質構造の形状およびキャリア濃度の違いとインピーダンス特性について
伊藤圭亮, ZHANG Xiaoyi, 熊崎祐介, 佐藤威友
応用物理学会春季学術講演会講演予稿集(CD-ROM), 01 Mar. 2017, Japanese

光電気化学反応を利用したn‐GaN表面ダメージ層の除去
枝元将彰, 松本悟, 熊崎祐介, 佐藤威友
応用物理学会春季学術講演会講演予稿集(CD-ROM), 01 Mar. 2017, Japanese

電気化学堆積法によるCu₂O/InPヘテロ界面の形成(3)
近江沙也夏, 熊崎祐介, 佐藤威友
応用物理学会春季学術講演会講演予稿集(CD-ROM), 01 Mar. 2017, Japanese

電気化学的手法を用いたGaN多孔質構造の選択領域形成
松本悟, 熊崎祐介, 佐藤威友
応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集, 07 Jan. 2017, Japanese

AlGaN/GaNヘテロ構造の電気化学的リセス加工における反応キャリア供給過程の影響
植村圭佑, 熊崎祐介, 佐藤威友
応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集, 07 Jan. 2017, Japanese

GaN多孔質構造の形状によるインピーダンス特性の分析
伊藤圭亮, ZHANG Xiaoyi, 熊崎祐介, 佐藤威友
応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集, 07 Jan. 2017, Japanese

Electrochemical formation of N-type GaN and N-type InP porous structures for chemical sensor applications　　　　　　　　　　　　　　　
T. Sato, X. Zhang, K. Ito, S. Matsumoto, Y. Kumazaki
IEEE SENSORS 2016, Nov. 2016, English, Poster presentation
[International presentation]

Precise Structural Tuning of Porous GaN Using Two-Step Anisotropic Etching for Optical and Photo-Electric Applications　　　　　　　　　　　　　　　
Y. Kumazaki, S. Matsumoto, T. Sato
2016 Pacific Rim Meeting on Electrochemistry and Solid State Science (PRiME 2016), Oct. 2016, English, Oral presentation
[International presentation]

Electrochemical Formation and Characterization of Cu2O Films on n-type InP Porous Structures　　　　　　　　　　　　　　　
S. Omi, Y. Kumazaki, T. Sato
2016 Pacific Rim Meeting on Electrochemistry and Solid State Science (PRiME 2016), Oct. 2016, English, Poster presentation
[International presentation]

GaN多孔質構造の選択領域形成に関する検討
松本悟, 熊崎祐介, 佐藤威友
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 01 Sep. 2016, Japanese

電気化学堆積法によるCu₂O/InP多孔質構造ヘテロ界面の形成
近江沙也夏, 熊崎祐介, 佐藤威友
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 01 Sep. 2016, Japanese

金属有機化合物分解法によるGaN表面へのNiO粒子の形成(2)
喜田弘文, 伊藤圭亮, 熊崎祐介, 渡久地政周, 佐藤威友
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 01 Sep. 2016, Japanese

電気化学インピーダンス分光法によるGaN多孔質構造の評価
伊藤圭亮, ZHANG Xiaoyi, 喜田弘文, 熊崎祐介, 佐藤威友
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 01 Sep. 2016, Japanese

AlGaN/GaNヘテロ構造の光電気化学特性と低損傷加工技術への応用
熊崎祐介, 植村圭佑, 佐藤威友
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 01 Sep. 2016, Japanese

電気化学堆積法によるCu₂O/InPヘテロ界面の形成
近江沙也夏, 熊崎祐介, 佐藤威友
応用物理学会春季学術講演会講演予稿集(CD-ROM), 03 Mar. 2016, Japanese

異方性ウェットエッチングによるGaN多孔質構造の作製と光学特性評価
熊崎祐介, 松本悟, 佐藤威友
応用物理学会春季学術講演会講演予稿集(CD-ROM), 03 Mar. 2016, Japanese

金属有機化合物分解法によるGaN表面へのNiO粒子の形成
喜田弘文, 伊藤圭亮, 熊崎祐介, 佐藤威友
応用物理学会春季学術講演会講演予稿集(CD-ROM), 03 Mar. 2016, Japanese

光電気化学反応を利用したGaN表面の陽極酸化
枝元将彰, 熊崎祐介, 佐藤威友
応用物理学会春季学術講演会講演予稿集(CD-ROM), 03 Mar. 2016, Japanese

Interface control technologies for high-power GaN transistors: Self-stopping etching of p-GaN layers utilizing electrochemical reactions　　　　　　　　　　　　　　　
T. Sato, Y. Kumazaki, M. Edamoto, M. Akazawa, T. Hashizume
SPIE Photonics West 2016, Feb. 2016, English, Invited oral presentation
[Invited], [International presentation]

Photoelectric energy conversion in GaN porous nanostructures formed by electrochemical process　　　　　　　　　　　　　　　
T. Sato, Y. Kumazaki, T. Hashizume
Energy, Materials and Nanotechnology, Dec. 2015, English, Invited oral presentation
[Invited], [International presentation]

Size-controlled formation of high-aspect ratio porous nanostructures on GaN substrates utilizing photo-assisted electrochemical etching for photovoltaic applications　　　　　　　　　　　　　　　
Y. Kumazaki, Z. Yatabe, T. Sato
2015 MRS Fall Meeting & Exhibit, Nov. 2015, English, Poster presentation
[International presentation]

Effect of High Electric Field on Photoabsorption Properties of GaN Porous Structures　　　　　　　　　　　　　　　
T. Sato, Y. Kumazaki, Z. Yatabe
228th ECS meeting, Hyatt Regency Phoenix and Phoenix Convention Center, Oct. 2015, English, Oral presentation
[International presentation]

Formation of Self-aligned Pore Arrays on n-GaN Substrates by Photo-assisted Electrochemical Etching Process　　　　　　　　　　　　　　　
Y. Kumazaki, T. Sato, Z. Yatabe
2015 International Conference on Solid State Devices and Materials (SSDM 2015), Sep. 2015, English, Oral presentation
[International presentation]

裏面光照射電気化学法によるGaN陽極酸化表面の分析
枝元将彰, 熊崎祐介, 谷田部然治, 佐藤威友
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 31 Aug. 2015, Japanese

電気化学堆積法によるCu₂O/InPヘテロ構造の形成と特性評価
近江沙也夏, 熊崎祐介, 谷田部然治, 佐藤威友
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 31 Aug. 2015, Japanese

Cu₂O/GaNヘテロ構造の電気化学形成と光学的特性評価
熊崎祐介, 近江沙也夏, 谷田部然治, 佐藤威友
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 31 Aug. 2015, Japanese

光触媒水分解システムを用いたn‐GaN多孔質構造の光電気化学的評価
喜田弘文, 熊崎祐介, 谷田部然治, 佐藤威友
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 31 Aug. 2015, Japanese

High-selective etching of p-GaN layers on AlGaN/GaN heterostructures by electrochemical process　　　　　　　　　　　　　　　
M. Edamoto, Y. Kumazaki, Z. Yatabe, T. Sato, T. Hashizume
11th Topical Workshop on Heterostructure Microelectronics (TWHM 2015), Aug. 2015, English, Poster presentation
[International presentation]

Electrochemical Formation of Cu2O Films on n-type InP and n-type GaN Substrates　　　　　　　　　　　　　　　
S. Omi, Y. Kumazaki, Z. Yatabe, T. Sato
11th Topical Workshop on Heterostructure Microelectronics (TWHM 2015), Aug. 2015, English, Poster presentation
[International presentation]

Photoelectrochemical characterization of n-type GaN porous structures for use in photocatalytic water-splitting system　　　　　　　　　　　　　　　
H. Kida, Y. Kumazaki, Z. Yatabe, T. Sato
11th Topical Workshop on Heterostructure Microelectronics (TWHM 2015), Aug. 2015, English, Poster presentation
[International presentation]

Influence of dry etching on Al2O3/AlGaN/GaN MOS interface properties　　　　　　　　　　　　　　　
Z. Yatabe, J. Ohira, T. Sato, T. Hashizume
11th Topical Workshop on Heterostructure Microelectronics (TWHM 2015), Aug. 2015, English, Poster presentation
[International presentation]

Electrochemical formation of GaN porous structures for photocatalytic applications　　　　　　　　　　　　　　　
T. Sato, Y. Kumazaki, Z. Yatabe
11th Topical Workshop on Heterostructure Microelectronics (TWHM 2015), Aug. 2015, English, Invited oral presentation
[Invited], [International presentation]

Electrochemical formation and UV photoresponse properties of GaN porous structures
喜田弘文, 熊崎祐介, 谷田部然治, 佐藤威友
電子情報通信学会技術研究報告, 27 Jul. 2015, Japanese

Spectro-electrochemical characterization of GaN/electrolyte interface and its application to the nanostructure formation
熊崎祐介, 渡部晃生, 谷田部然治, 佐藤威友
電子情報通信学会技術研究報告, 21 May 2015, Japanese

ドライエッチングがAl₂O₃/AlGaN/GaN構造のMOS界面特性に与える影響
谷田部然治, 大平城二, 佐藤威友, 橋詰保
応用物理学会春季学術講演会講演予稿集(CD-ROM), 26 Feb. 2015, Japanese

電気化学堆積法によるCu₂O/GaNヘテロ構造の形成と特性評価
熊崎祐介, 近江沙也夏, 谷田部然治, 佐藤威友
応用物理学会春季学術講演会講演予稿集(CD-ROM), 26 Feb. 2015, Japanese

電気化学エッチングによるGaN多孔質構造の形成
渡部晃生, 熊崎祐介, 谷田部然冶, 佐藤威友
応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集, 09 Jan. 2015, Japanese

デバイス応用に向けた6H‐SiC上グラフェンの高品質・多機能化
宮本貴雄, 小西敬太, 佐藤威友
応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集, 09 Jan. 2015, Japanese

Correlation between growth time and carrier density in epitaxial graphene on 6H-SiC　　　　　　　　　　　　　　　
T. Miyamoto, K. Konishi, T. Sato
The 7th International Symposium on Surface Science (ISSS2014), Nov. 2014, English, Poster presentation
[International presentation]

Structural Properties and Control of GaN Porous Nanostructures Formed by Photo-assisted Electrochemical Process　　　　　　　　　　　　　　　
A. Watanabe, Y. Kumazaki, Z. Yatabe, T. Sato
The 7th International Symposium on Surface Science (ISSS2014), Nov. 2014, English, Poster presentation
[International presentation]

Enhanced spin-orbit interaction in the hydrogenated epitaxial graphene on silicon carbide　　　　　　　　　　　　　　　
K. Konishi, T. Miyamoto, K. Yoh, T. Sato
27th International Microprocesses and Nanotechnology Conference (MNC2014), Nov. 2014, English, Poster presentation
[International presentation]

Electrochemical Formation of GaN Porous Structures Under UV-Light Irradiation for Photoelectrochemical Application　　　　　　　　　　　　　　　
T. Sato, A. Watanabe, Y. Kumazaki, Z. Yatabe
2014 ECS and SMEQ Joint International Meeting, Oct. 2014, English, Oral presentation
[International presentation]

電気化学エッチングを用いた窒化物半導体多孔質構造の形成
渡部晃生, 熊崎祐介, 谷田部然治, 佐藤威友
電気化学秋季大会講演要旨集, 27 Sep. 2014, Japanese

III‐V族化合物半導体の電気化学エッチングと微細加工への応用
佐藤威友, 熊崎祐介, 渡部晃生, 谷田部然治
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 01 Sep. 2014, Japanese

6H‐SiC上グラフェンにおける成長時間とキャリア密度の関係
宮本貴雄, 小西敬太, 佐藤威友
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 01 Sep. 2014, Japanese

電気化学エッチングによるGaN多孔質構造の形成と形状制御の向上
熊崎祐介, 渡部晃生, 谷田部然治, 佐藤威友
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 01 Sep. 2014, Japanese

Correlation between Structural and Optical Properties of GaN Porous Structures Formed by Photo-assisted Electrochemical Etching　　　　　　　　　　　　　　　
Y. Kumazaki, A. Watanabe, Z. Yatabe, T. Sato
The International Workshop on Nitride Semiconductors 2014 (IWN2014), Aug. 2014, English

Interface Trap States in Al2O3/AlGaN/GaN Structure Induced by ICP Etching of AlGaN Surfaces　　　　　　　　　　　　　　　
Z. Yatabe, T. Sato, T. Hashizume
The International Workshop on Nitride Semiconductors 2014 (IWN2014), Aug. 2014, English
[Invited]

Structural control of GaN porous structures for high-sensitive chemical sensors　　　　　　　　　　　　　　　
A. Watanabe, Y. Kumazaki, Z. Yatabe, T. Sato
The 6th IEEE International Nanoelectronics Conference 2014 (INEC-2014), Jul. 2014, English

Electrochemical Formation of III-V Semiconductor Porous Nanostructures　　　　　　　　　　　　　　　
T. Sato, Y. Kumazaki, A. Watanabe, Z. Yatabe
The 6th IEEE International Nanoelectronics Conference 2014 (INEC-2014), Jul. 2014, English
[Invited]

電気化学的手法によるIII-V族半導体多孔質構造の形成と高感度化学センサへの応用
SATO Taketomo, WATANABE Akio, KUMAZAKI Yusuke
公益社団法人電気化学会第81回大会, 29 Mar. 2014, Japanese, Oral presentation
[Domestic Conference]

ELECTROCHEMICAL FORMATION OF III-V SEMICONDUCTOR POROUS STRUCTURES FOR HIGHT-SENSITIVE SENSOR APPRICATIONS
佐藤威友, 渡部晃生, 熊崎祐介
Chem Sens, 29 Mar. 2014, Japanese

GaNパワー素子のための絶縁膜界面制御
HASHIZUME Tamotsu, YATABE Zenji, SATO Taketomo
電気学会電子デバイス研究会, 13 Mar. 2014, Japanese, Invited oral presentation
[Invited], [Domestic Conference]

窒化物半導体異種接合の評価と制御
佐藤威友, 赤澤正道, 橋詰保
応用物理学会春季学術講演会講演予稿集(CD-ROM), 03 Mar. 2014, Japanese, Invited oral presentation
[Invited], [Domestic Conference]

AlGaN/GaNヘテロ構造上に形成したp‐GaN層の選択的電気化学エッチング
熊崎祐介, 佐藤威友, 橋詰保, 橋詰保
応用物理学会春季学術講演会講演予稿集(CD-ROM), 03 Mar. 2014, Japanese, Oral presentation
[Domestic Conference]

GaN多孔質構造の形状制御と化学センサへの応用
渡部晃生, 熊崎祐介, 谷田部然冶, 佐藤威友
応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集, 09 Dec. 2013, Japanese, Oral presentation
[Domestic Conference]

Photoabsorption and Photoelectric Conversion Properties of InP Porous Structures Formed by Electrochemical Process　　　　　　　　　　　　　　　
SATO Taketomo, KUMAZAKI Yusuke, JINBO Ryohei, YATABE Zenji
224th Meeting of the Electrochemical Society（CD-ROM）, Oct. 2013, English, Oral presentation
[International presentation]

Structural and Optical Characterization of GaN Porous Structures Formed by Photo-assisted Electrochemical Process　　　　　　　　　　　　　　　
KUMAZAKI Yusuke, WATANABE Akio, YATABE Zenji, SATO Taketomo
224th Meeting of the Electrochemical Society（CD-ROM）, Oct. 2013, English, Poster presentation
[International presentation]

電気化学的手法と裏面光照射によるGaN多孔質ナノ構造の形成
渡部晃生, 熊崎祐介, 谷田部然治, 佐藤威友
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 31 Aug. 2013, Japanese

GaN多孔質ナノ構造の表面形状と光電気化学特性
熊崎祐介, 渡部晃生, 谷田部然治, 佐藤威友
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 31 Aug. 2013, Japanese

Selective etching of p-GaN layers for normally-off AlGaN/GaN HEMTs by electrochemical process　　　　　　　　　　　　　　　
KUMAZAKI Yusuke, AZUMAISHI Naoki, UEDA Hiroyuki, KANECHIKA Masakazu, TOMITA Hidemoto, SATO Taketomo, HASHIZUME Tamotsu
10th International Conference on Nitride Semiconductors (ICNS-10), Aug. 2013, English, Poster presentation
[International presentation]

Electrochemical Formation and Optical Characterization of GaN Porous Structures　　　　　　　　　　　　　　　
KUMAZAKI Yusuke, WATANABE Akio, JINBO Ryohei, YATABE Zenji, SATO Taketomo
32nd Electronic Materials Symposium (EMS32), Jul. 2013, English
[International presentation]

電気化学的手法による半導体多孔質構造の形成と機能素子への応用　　　　　　　　　　　　　　　
SATO Taketomo
第 29 回ライックセミナー・第 19 回若手研究者交流会, Jun. 2013, English, Public discourse
[Invited], [International presentation]

電気化学的手法によるGaN多孔質構造の形成と光学特性の評価　　　　　　　　　　　　　　　
KUMAZAKI Yusuke, WATANABE Akio, YATABE Zenji, SATO Taketomo
第 29 回ライックセミナー・第 19 回若手研究者交流会, Jun. 2013, English, Public discourse
[International presentation]

Photoabsorption and Photoelectric Conversion Properties of InP Porous Structures Formed by the Electrochemical process
KUMAZAKI YUSUKE, JIMBO RYOHEI, YATABE ZENJI, SATO TAKETOMO
電子情報通信学会技術研究報告, 09 May 2013, Japanese

Electrochemical Formation and Optical Characterization of GaN Porous Structures　　　　　　　　　　　　　　　
KUMAZAKI Yusuke, WATANABE Akio, JINBO Ryohei, YATABE Zenji, SATO Taketomo
The 40th International Symposium on Compound Semiconductors (ISCS2013), May 2013, English, Poster presentation
[International presentation]

電気化学的手法によるGaN多孔質構造の形成と光学特性の評価
熊崎祐介, 渡部晃生, 神保亮平, 谷田部然治, 佐藤威友
応用物理学会春季学術講演会講演予稿集(CD-ROM), 11 Mar. 2013, Japanese

InP多孔質構造孔壁表面の機能化による光電変換素子への応用
神保亮平, 渡部晃生, 佐藤威友
応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集, 11 Jan. 2013, Japanese

High-sensitive ISFETs Based on Semiconductor Porous Nanostructures　　　　　　　　　　　　　　　
SATO Taketomo
BIT’s 3rd Annual World Congress of NanoMedicine-2012, 01 Nov. 2012, English, Oral presentation
[Invited], [International presentation]

Photoelectric-conversion Devices Based on InP Porous Structure　　　　　　　　　　　　　　　
SATO Taketomo, JINBO Ryohei, YATABE Zenji
2012 Pacific Rim Meeting on Electrochemical and Solid-State Science, 07 Oct. 2012, English, Oral presentation
[International presentation]

Optical Absorption Properties of InP Porous Structures Formed by Electrochemical Process　　　　　　　　　　　　　　　
KUMAZAKI Yusuke, KUDO, Tomohito, YATABE Zenji, SATO Taketomo
2012 International Conference on Solid State Devices and Materials, 25 Sep. 2012, English, Poster presentation
[International presentation]

pn接合基板上に形成したInP多孔質構造の光学応答特性の評価
熊崎祐介, 工藤智人, 谷田部然冶, 佐藤威友
応用物理学会学術講演会講演予稿集(CD-ROM), 27 Aug. 2012, Japanese
[Domestic Conference]

ポリスチレン微小球の自己組織化配列とリソグラフィ技術を利用した半導体加工基板の作製
神保亮平, 今井雄大, 谷田部然治, 佐藤威友
応用物理学会学術講演会講演予稿集(CD-ROM), 27 Aug. 2012, Japanese
[Domestic Conference]

電気化学的手法によるInP多孔質構造の形成と孔の位置制御
神保亮平, 谷田部然冶, 佐藤威友
応用物理学関係連合講演会講演予稿集(CD-ROM), 29 Feb. 2012, Japanese
[Domestic Conference]

Photo-electrical response of InP porous structures formed on pn substrates　　　　　　　　　　　　　　　
KUDO Tomohito, SATO Taketomo
Extended Abstracts of the 2011 International Symposium on Surface Science, Dec. 2011, English
[International presentation]

Photoelectric Conversion Devices based on InP Porous Structures　　　　　　　　　　　　　　　
JINBO Ryohei, KUDO Tomohito, SATO Taketomo
Extended Abstracts of the 2011 International Conference on Solid State Devices and Materials, Sep. 2011, English
[International presentation]

電気化学的手法を用いたInP多孔質構造の形成と光電変換素子への応用
神保亮平, 岡崎拓行, 佐藤威友
応用物理学会学術講演会講演予稿集(CD-ROM), 16 Aug. 2011, Japanese
[Domestic Conference]

pn接合基板に形成したInP多孔質構造の光応答特性
工藤智人, 佐藤威友
応用物理学会学術講演会講演予稿集(CD-ROM), 16 Aug. 2011, Japanese
[Domestic Conference]

ポリスチレン微小球の自己組織化配列とリソグラフィ技術を利用した多孔質構造の形成
今井雄大, 神保亮平, 谷田部然治, 佐藤威友
応用物理学会学術講演会講演予稿集(CD-ROM), 16 Aug. 2011, Japanese
[Domestic Conference]

ドライエッチしたGaNおよびAlGaN表面の評価と制御
谷田部然冶, 東石直樹, 佐藤威友, 橋詰保
応用物理学会学術講演会講演予稿集(CD-ROM), 16 Aug. 2011, Japanese
[Domestic Conference]

ポリスチレン微小球の自己組織化配列とリソグラフィ技術を利用した半導体パターニング技術
今井雄大, 岡崎拓行, 佐藤威友
応用物理学関係連合講演会講演予稿集(CD-ROM), 09 Mar. 2011, Japanese
[Domestic Conference]

InP多孔質構造を利用した光電変換素子の検討
工藤智人, 岡崎拓行, 佐藤威友
応用物理学関係連合講演会講演予稿集(CD-ROM), 09 Mar. 2011, Japanese
[Domestic Conference]

電気化学的手法によるInPポーラス孔壁表面の機能化と電気的特性の評価
岡崎拓行, 神保亮平, 佐藤威友
化学系学協会北海道支部冬季研究発表会講演要旨集, 01 Feb. 2011, Japanese
[Domestic Conference]

ポリスチレン微小球の自己組織化配列を利用した半導体マイクロパターニング技術
今井雄大, 岡崎拓行, 佐藤威友
応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集, 07 Jan. 2011, Japanese
[Domestic Conference]

pn接合基板上に形成したInP多孔質構造の光応答特性
工藤智人, 岡崎拓行, 佐藤威友
応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集, 07 Jan. 2011, Japanese
[Domestic Conference]

High-Sensitive ISFETs based on InP Porous Structures　　　　　　　　　　　　　　　
SATO Taketomo, YOSHIZAWA Naoki
The 61st Annual Meeting of the International Society of Electrochemistry（CD-ROM）, Sep. 2010, English
[International presentation]

電気化学的手法によるInP多孔質構造の形成と孔壁表面の機能化
岡崎拓行, 佐藤威友
応用物理学会学術講演会講演予稿集(CD-ROM), 30 Aug. 2010, Japanese
[Domestic Conference]

ポリスチレン微小球の自己組織化配列を利用したマイクロパターニングと半導体微細加工への応用
今井雄大, 岡崎拓行, 佐藤威友
応用物理学会学術講演会講演予稿集(CD-ROM), 30 Aug. 2010, Japanese
[Domestic Conference]

InP多孔質構造の光吸収特性と光電変換
佐藤威友, 岡崎拓行
応用物理学会学術講演会講演予稿集(CD-ROM), 30 Aug. 2010, Japanese
[Domestic Conference]

多孔質構造を有するイオン感応性電界効果トランジスタ
佐藤威友, 岡崎拓行
応用物理学会学術講演会講演予稿集(CD-ROM), 30 Aug. 2010, Japanese
[Domestic Conference]

pn接合基板上に形成したInP多孔質構造の電気的評価
工藤智人, 岡崎拓行, 佐藤威友
応用物理学会学術講演会講演予稿集(CD-ROM), 30 Aug. 2010, Japanese
[Domestic Conference]

Optical and Electrical Properties of InP Porous Structures Formed on P-N Substrates　　　　　　　　　　　　　　　
OKAZAKI Hiroyuki, SATO Taketomo, YOSHIZAWA Naoki, HASHIZUME Tamotsu
2010 International Conference on Indium Phosiphide and Related Materials, May 2010, English
[International presentation]

電気化学的手法を用いて形成したInPポーラス構造の電気的特性
岡崎拓行, 吉澤直樹, 佐藤威友, 橋詰保
応用物理学関係連合講演会講演予稿集(CD-ROM), 03 Mar. 2010, Japanese
[Domestic Conference]

Optical and electrical properties of InP porous structures formed on p-n substrates　　　　　　　　　　　　　　　
OKAZAKI Hiroyuki, YOSHIZAWA Naoki, SATO Taketomo, HASHIZUME Tamotsu
2010 International RCIQE/CREST Joint Workshop, 01 Mar. 2010, English
[International presentation]

InP‐pn接合基板へのポーラス構造作製と形状および位置の制御
岡崎拓行, 吉澤直樹, 佐藤威友
応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集, 08 Jan. 2010, Japanese
[Domestic Conference]

InP‐pn接合基板へのポーラス構造形成および電気的特性評価
吉澤直樹, 岡崎拓行, 佐藤威友, 橋詰保
応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集, 08 Jan. 2010, Japanese
[Domestic Conference]

Low Reflectance Surface Observed on InP Porous Structures after Photoelectrochemical Etching　　　　　　　　　　　　　　　
SATO Taketomo, YOSHIZAWA Naoki, OKAZAKI Hiroyuki, HASHIZUME Tamotsu
216th Meeting of the Electrochemical Society（CD-ROM）, Oct. 2009, English
[International presentation]

InP‐pn接合基板へのポーラス構造作製と形状制御
岡崎拓行, 吉澤直樹, 佐藤威友
応用物理学会学術講演会講演予稿集, 08 Sep. 2009, Japanese
[Domestic Conference]

ポーラス構造を形成したInP‐pn接合基板の電気的特性
吉澤直樹, 岡崎拓行, 佐藤威友, 橋詰保
応用物理学会学術講演会講演予稿集, 08 Sep. 2009, Japanese
[Domestic Conference]

Formation and application of InP porous structures on p-n substrates　　　　　　　　　　　　　　　
SATO Taketomo, YOSHIZAWA Naoki, OKAZAKI Hiroyuki, HASHIZUME Tamotsu
2009 Asia-Pacific Workshop on Fundamentals and Applications of Advanced Semiconductor Devices（CD-ROM）, Jun. 2009, English
[International presentation]

pH Response Characteristics of Liquid-phase Chemical Sensors using InP Open-gate FETs　　　　　　　　　　　　　　　
YOSHIZAWA Naoki, SATO Taketomo, MIZOHATA Akinori, HASHIZUME Tamotsu
2009 RCIQE International Seminar on "Advanced Semiconductor Materials and Devices", 02 Mar. 2009, English
[International presentation]

Electrochemical formation and sensor application of InP porous nanostructures　　　　　　　　　　　　　　　
SATO Taketomo, MIZOHATA Akinori, YOSHIZAWA Naoki, HASHIZUME Tamotsu
2009 RCIQE International Seminar on "Advanced Semiconductor Materials and Devices", 02 Mar. 2009, English
[International presentation]

pH Sensitivity of Liquid-phase Chemical Sensors using InP Open-gate FETs　　　　　　　　　　　　　　　
YOSHIZAWA Naoki, SATO Taketomo, MIZOHATA Akinori, HASHIZUME Tamotsu
2008 International Symposium on Surface Science and Nanotechnology, Nov. 2008, English
[International presentation]

Liquid-phase Chemical Sensors using InP-based Open-gate FETs　　　　　　　　　　　　　　　
YOSHIZAWA Naoki, SATO Taketomo, MIZOHATA Akinori
The Seventh IEEE Conference on Sensors, Oct. 2008, English
[International presentation]

Complete Removal of Irregular Top Layer for Sensor Applications of InP Porous Nanostructures　　　　　　　　　　　　　　　
SATO Taketomo, MIZOHATA Akinori, YOSHIZAWA Naoki, HASHIZUME Tamotsu
2008 Pacific Rim Meeting on Electrochemicao and Solid-State Science (CD-ROM), Oct. 2008, English
[International presentation]

InPイオン感応性電界効果トランジスタのpH応答特性
吉澤直樹, 溝畑彰規, 佐藤威友, 橋詰保
応用物理学会学術講演会講演予稿集, 02 Sep. 2008, Japanese
[Domestic Conference]

グリコール水溶液を用いた陽極酸化によるGaN表面の電気的・光学的安定化
塩崎奈々子, 塩崎奈々子, 佐藤威友, 佐藤威友, 橋詰保, 橋詰保
応用物理学会学術講演会講演予稿集, 02 Sep. 2008, Japanese
[Domestic Conference]

InPポーラス構造を基盤とする電流検出型化学センサの作製
溝畑彰規, 吉澤直樹, 佐藤威友, 橋詰保
応用物理学会学術講演会講演予稿集, 02 Sep. 2008, Japanese
[Domestic Conference]

電気化学プロセスによるInPポーラス構造の形成と縦および横方向へのエッチング制御
佐藤威友, 溝畑彰規, 吉澤直樹, 橋詰保
応用物理学会学術講演会講演予稿集, 02 Sep. 2008, Japanese
[Domestic Conference]

Electrochemical formation and functionalization of InP porous nanostructures and their application to chemical sensors　　　　　　　　　　　　　　　
MIZOHATA Akinori, YOSHIZAWA Naoki, SATO Taketomo, HASHIZUME Tamotsu
2008 Asia-Pacific Workshop on Fundamentals and Applications of Advanced Semiconductor Devices, Jul. 2008, English
[International presentation]

電気化学的手法によるGaN表面酸化膜形成と表面安定化への応用
塩崎奈々子, 佐藤威友, 橋詰保
応用物理学関係連合講演会講演予稿集, 27 Mar. 2008, Japanese
[Domestic Conference]

電気化学的手法によるInP表面の機能性修飾と電流検出型化学センサへの応用
溝畑彰規, 佐藤威友, 橋詰保
応用物理学関係連合講演会講演予稿集, 27 Mar. 2008, Japanese
[Domestic Conference]

Electrochemical formation and sensor application of highly-ordered InP nanostructures　　　　　　　　　　　　　　　
SATO Taketomo, MIZOHATA Akinori, YOSHIZAWA Naoki, HASHIZUME Tamotsu
2008 RCIQE International Seminar on "Advanced Semiconductor Materials and Devices", 03 Mar. 2008, English
[International presentation]

電気化学的手法によるInP表面の機能性修飾と化学センサへの応用
溝畑彰規, 佐藤威友, 橋詰保
応用物理学会北海道支部・日本光学会北海道支部合同学術講演会講演予稿集, 10 Jan. 2008, Japanese
[Domestic Conference]

陽極酸化によりn‐GaN上に形成された酸化膜の評価と応用
塩崎奈々子, 石川史太郎, TRAMPERT A, GRAHN H. T, 佐藤威友, 橋詰保
応用物理学会学術講演会講演予稿集, 04 Sep. 2007, Japanese
[Domestic Conference]

電気化学的手法によるInPポーラスナノ構造の形成と化学センサへの応用
佐藤威友, 溝畑彰規, 橋詰保
応用物理学会学術講演会講演予稿集, 04 Sep. 2007, Japanese
[Domestic Conference]

グリコール水溶液を用いた電気化学プロセスによるGaN表面酸化薄膜の形成
塩崎奈々子, 佐藤威友, 橋詰保
応用物理学関係連合講演会講演予稿集, 27 Mar. 2007, Japanese
[Domestic Conference]

二段階電気化学プロセスによるInPナノ構造の形成とサイズ制御
佐藤威友, 佐藤威友, 藤野敏幸, 藤野敏幸, 橋詰保, 橋詰保
応用物理学関係連合講演会講演予稿集, 27 Mar. 2007, Japanese
[Domestic Conference]

SiNx/CN/GaN構造を用いた炭素固相拡散の検討
木村健, 佐藤威友, 橋詰保
応用物理学関係連合講演会講演予稿集, 27 Mar. 2007, Japanese
[Domestic Conference]

Electrochemical formation and optical characterization of size-controlled InP porous nanostructures　　　　　　　　　　　　　　　
SATO Taketomo, FUJINO Toshiyuki, HASHIZUME Tamotsu
The 4th International Symposium on Ubiquitous Knowledge Network Environment, Meme-Media Technology Approach to the R&D of Next-Generation Information Technologies, Mar. 2007, English
[International presentation]

Chemical sensors using open-gate AlGaN/GaN transistor structures　　　　　　　　　　　　　　　
KOKAWA Takuya, SATO Taketomo, HASHIZUME Tamotsu
The 4th International Symposium on Ubiquitous Knowledge Network Environment, Meme-Media Technology Approach to the R&D of Next-Generation Information Technologies, Mar. 2007, English
[International presentation]

Electrochemical formation of high-density array of InP nanostructures　　　　　　　　　　　　　　　
SATO TAKATOMO
2007 RCIQE International Seminar on "Advanced Semiconductor Materials and Devices", 08 Feb. 2007, English
[International presentation]

Electrochemical Formation and Sensor Application of InP Porous Nanostructures　　　　　　　　　　　　　　　
2007 Asia-Pacific Workshop on Fundamentals and Applications of Advanced Semiconductor Devices, 2007

Electrochemical Formation of InP Porous Nanostructures and Its Application to Amperometric Chemical Sensors　　　　　　　　　　　　　　　
2007 European Materials Research Society Fall Meeting, 2007

電気化学的連続プロセスによるInPポーラス構造のサイズ制御
藤野敏幸, 佐藤威友, 橋詰保
応用物理学会学術講演会講演予稿集, 29 Aug. 2006, Japanese
[Domestic Conference]

電気化学プロセスを施したGaNおよびAlGaN表面構造の評価
塩崎奈々子, 佐藤威友, 橋詰保
応用物理学会学術講演会講演予稿集, 29 Aug. 2006, Japanese
[Domestic Conference]

ヘキサゴナルBDD回路高密度実装に適した化合物半導体ナノ細線デバイスの検討
田村隆博, 葛西誠也, 佐藤威友, 橋詰保
応用物理学会学術講演会講演予稿集, 29 Aug. 2006, Japanese
[Domestic Conference]

AlGaN/GaNオープンゲートHFETの溶液中でのふるまい
古川拓也, 佐藤威友, 橋詰保
応用物理学会学術講演会講演予稿集, 29 Aug. 2006, Japanese
[Domestic Conference]

Ptショットキーゲートを用いた高感度InP水素センサーの検討
木村健, 佐藤威友, 橋詰保, 長谷川英機
応用物理学関係連合講演会講演予稿集, 22 Mar. 2006, Japanese
[Domestic Conference]

AlGaN/GaNオープンゲートFETを用いた化学センサ
古川拓也, 佐藤威友, 長谷川英機, 橋詰保
応用物理学関係連合講演会講演予稿集, 22 Mar. 2006, Japanese
[Domestic Conference]

陽極酸化エッチングプロセスを用いた化合物半導体微細構造の作製
塩崎奈々子, 佐藤威友, 長谷川英機, 橋詰保
応用物理学関係連合講演会講演予稿集, 22 Mar. 2006, Japanese
[Domestic Conference]

加工基板へのGaN/AlGaNヘテロ構造の選択的MBE成長と埋め込み細線の形成
佐藤威友, 佐藤威友, 及川武, 及川武, 長谷川英機, 長谷川英機
応用物理学関係連合講演会講演予稿集, 22 Mar. 2006, Japanese
[Domestic Conference]

MBE選択成長GaAsヘキサゴナルネットワークの形成とBDD節点デバイスの集積化
田村隆博, 玉井功, 葛西誠也, 佐藤威友, 長谷川英機, 橋詰保
応用物理学関係連合講演会講演予稿集, 22 Mar. 2006, Japanese
[Domestic Conference]

電気化学プロセスにより作製したInPナノ構造の光学的特性
藤野敏幸, 木村健, 佐藤威友, 長谷川英機, 橋詰保
応用物理学関係連合講演会講演予稿集, 22 Mar. 2006, Japanese
[Domestic Conference]

Optical Properties of Size-controlled Porous Nanostructures Formed on n-InP (001) Substrates by Electrochemical Process　　　　　　　　　　　　　　　
FUJINO Toshiyuki, SATO Taketomo, HASHIZUME Tamotsu
2006 International Conference on Solid State Devices and Materials, 2006, English
[International presentation]

Self-assembled Formation of Uniform Arrays of InP Nanopores and Nanowires by Electrochemical Process　　　　　　　　　　　　　　　
SATO Taketomo, FUJINO Toshiyuki, HASHIZUME Tamotsu
210th Meeting of the Electrochemical Society, 2006, English
[International presentation]

Self-Assembled Formation of Uniform Arrays of InP Nanopores and Nanowires by Electrochemical Process　　　　　　　　　　　　　　　
210th Joint International Meeting of Electrochemical Society, 2006

Selective MBE Growth of Shape- Size- and Position- Controlled GaAs Nanowire Networks on (111)B Patterned Substrates　　　　　　　　　　　　　　　
TAMAI Isao, SATO Taketomo, HASEGAWA Hideki
International Semiconductor Device Research Symposium, 07 Dec. 2005, English
[International presentation]

Self-Organized Formation of Chaotic and Regular Nanostructures on (001) and (111) InP Substrates by Electrochemical Anodization Process　　　　　　　　　　　　　　　
FUJINO Toshiyuki, KIMURA Takeshi, SATO Taketomo, HASEGAWA Hideki, HASHIZUME Tamotsu
International Symposium on Surface Science and Nanotechnology, 14 Nov. 2005, English
[International presentation]

Growth Simulation and Actual MBE Growth of Triangular GaAs Nanowires on Patterned (111)B Substrates　　　　　　　　　　　　　　　
TAMAI Isao, SATO Taketomo, HASEGAWA Hideki, HASHIZUME Tamotsu
International Symposium on Surface Science and Nanotechnology, 14 Nov. 2005, English
[International presentation]

Embedded Nanowire Network Growth and Node Device Fabrication for GaAs-Based High-Density Hexagonal BDD Quantum Circuits　　　　　　　　　　　　　　　
TAMURA Takahiro, TAMAI Isao, KASAI Seiya, SATO Taketomo, HASEGAWA Hideki, HASHIZUME Tamotsu
2005 Solid State Devices and Materials, 12 Sep. 2005, English
[International presentation]

Sensing Mechanism of InP Hydrogen Sensors Using Pt Schottky Diodes Formed by Electrochemical Process　　　　　　　　　　　　　　　
KIMURA Takeshi, HASEGAWA Hideki, SATO Taketomo, HASHIZUME Tamotsu
2005 Solid State Devices and Materials, 12 Sep. 2005, English
[International presentation]

MBE選択成長GaAs量子細線ネットワークの形成とヘキサゴナルBDD回路応用への検討
田村隆博, 玉井功, 葛西誠也, 佐藤威友, 長谷川英機, 橋詰保
応用物理学会学術講演会講演予稿集, 07 Sep. 2005, Japanese
[Domestic Conference]

RF‐MBE法によるGaN(0001)加工基板へのAlGaN/GaN成長と,その選択性
及川武, 佐藤威友, 長谷川英機, 橋詰保
応用物理学会学術講演会講演予稿集, 07 Sep. 2005, Japanese
[Domestic Conference]

電気化学プロセスによるInPポーラス構造の形成と制御
藤野敏幸, 佐藤威友, 長谷川英機, 橋詰保
応用物理学会学術講演会講演予稿集, 07 Sep. 2005, Japanese
[Domestic Conference]

(001)面メサ型加工基板への選択的MBE成長によるGaAs/AlGaAs細線の形成機構
佐藤威友, 玉井功, 長谷川英機
応用物理学会学術講演会講演予稿集, 07 Sep. 2005, Japanese
[Domestic Conference]

Pt/InPショットキーダイオードによる水素センシングのメカニズム考察
木村健, 佐藤威友, 長谷川英機, 橋詰保
応用物理学会学術講演会講演予稿集, 07 Sep. 2005, Japanese
[Domestic Conference]

陽極酸化とエッチングプロセスによるGaAs,AlGaAs微細加工の検討
塩崎奈々子, 佐藤威友, 赤沢正道, 長谷川英機, 橋詰保
応用物理学会学術講演会講演予稿集, 07 Sep. 2005, Japanese
[Domestic Conference]

MBE選択成長法を用いたGaAs(111)B加工基板へのGaAs/AxGa1-xAs量子細線の形成
玉井功, 佐藤威友, 長谷川英機, 橋詰保
応用物理学会学術講演会講演予稿集, 07 Sep. 2005, Japanese
[Domestic Conference]

Precisely Controlled Anodic Etching for Processing of GaAs-based Quantum Nanostructures and Devices　　　　　　　　　　　　　　　
SHIOZAKI Nanako, SATO Taketomo, AKAZAWA Masamichi, HASEGAWA Hideki
10th International Conference on the Formation of Semiconductor Interfaces (ICFSI-10), 03 Jul. 2005, English
[International presentation]

Selective MBE growth ofAlGaN/GaN quantum wire structures on pre-patterned GaN (0001) substrates and its growth mechanism　　　　　　　　　　　　　　　
OIKAWA Takeshi, SATO Taketomo, HASEGAWA Hideki
8th International Conference on Atomically Controlled Surfaces Interfaces and Nanostructures, 19 Jun. 2005, English
[International presentation]

MBE Growth and Si-interlayer Based Surface Passivation of GaAs Quantum Wires　　　　　　　　　　　　　　　
SHIOZAKI Nanako, SATO Taketomo, AKAZAWA Masamichi, HASEGAWA Hideki
29th Workshop on Compound Semiconductor Devices and Integrated Circuit, 16 May 2005, English
[International presentation]

Electrodeposited Pt/InP Schottky Barriers with Large Barrier Heights and Large Hydrogen Sensitivity for Sensor Chips Using InP-based Quantum Wire Networks　　　　　　　　　　　　　　　
KIMURA Takeshi, MATSUO Kazushi, SATO Taketomo, HASHIZUME, Tamotsu, HASEGAWA Hideki
17th Indium Phosphide and Related Materials Conference, 08 May 2005, English
[International presentation]

MBE選択成長法によるGaN(0001)加工基板上へのAlGaN/GaNナノ構造形成メカニズム
及川武, 佐藤威友, 橋詰保, 長谷川英機
応用物理学関係連合講演会講演予稿集, 29 Mar. 2005, Japanese
[Domestic Conference]

MBE選択成長GaAs量子細線ネットワークを適用したBDD量子節点デバイスの試作と評価
田村隆博, 湯元美樹, 玉井功, 葛西誠也, 佐藤威友, 長谷川英機
応用物理学関係連合講演会講演予稿集, 29 Mar. 2005, Japanese
[Domestic Conference]

GaAs(111)B加工基板へのMBE選択成長法による量子細線の形成とその形成メカニズム(2)
玉井功, 佐藤威友, 長谷川英機
応用物理学関係連合講演会講演予稿集, 29 Mar. 2005, Japanese
[Domestic Conference]

GaAs(001)および(111)B基板に作製したGaAs/AlGaAs量子細線の表面パッシベーション
塩崎奈々子, 玉井功, 佐藤威友, 長谷川英機
応用物理学関係連合講演会講演予稿集, 29 Mar. 2005, Japanese
[Domestic Conference]

〈-110〉方向に沿ったメサ型加工基板へのMBE成長とGaAsリッジ細線の形成過程
佐藤威友, 玉井功, 長谷川英機
応用物理学関係連合講演会講演予稿集, 29 Mar. 2005, Japanese
[Domestic Conference]

InP系材料を用いたPtショットキーダイオードによる水素ガスセンシング
木村健, 佐藤威友, 長谷川英機
応用物理学関係連合講演会講演予稿集, 29 Mar. 2005, Japanese
[Domestic Conference]

Growth Kinetics and Theoretical Modeling of Selective Molecular Beam Epitaxy for Growth of GaAs Nanowires on Non-planar Substrates　　　　　　　　　　　　　　　
SATO Taketomo, TAMAI Isao, HASEGAWA Hideki
2005 RCIQE International Seminar for 21st Century COE Program: Quantum Nanoelectronics for Meme-Media-Based Information Technologies (III), 08 Feb. 2005, English
[International presentation]

Investigation of Side-Gating Effects in GaAs-based Quantum Wire Transistor　　　　　　　　　　　　　　　
JIA Rui, KASAI Seiya, SATO Taketomo, HASEGAWA Hideki
2005 RCIQE International Seminar for 21st Century COE Program: Quantum Nanoelectronics for Meme-Media-Based Information Technologies (III), 08 Feb. 2005, English
[International presentation]

High-Density Hexagonal Nanowire Networks on Pre-Patterned GaAs (001) and (111)B Substrates by Selective MBE Growth　　　　　　　　　　　　　　　
TAMAI Isao, SATO Taketomo, HASEGAWA Hideki
2005 RCIQE International Seminar for 21st Century COE Program: Quantum Nanoelectronics for Meme-Media-Based Information Technologies (III), 08 Feb. 2005, English
[International presentation]

Effects of Surface States and Si-interlayer Based Surface Passivation on GaAs Quantum Wires Grown by Selective Molecular Beam Epitaxy　　　　　　　　　　　　　　　
SHIOZAKI Nanako, SATO Taketomo, HASEGAWA Hideki
32nd Conference on the Physics and Chemistry of Semiconductor Interfaces, 23 Jan. 2005, English
[International presentation]

Growth Kinetics and Theoretical Modeling of Selective Molecular Beam Epitaxy for Growth of GaAs Nanowires on Non-planar (111)B Substrates　　　　　　　　　　　　　　　
SATO Taketomo, TAMAI Isao, HASEGAWA Hideki
32nd Conference on the Physics and Chemistry of Semiconductor Interfaces, 23 Jan. 2005, English
[International presentation]

Self-assembled formation of InP nanopore arrays by photoelectrochemical anodization in HCl based electrolyte　　　　　　　　　　　　　　　
SATO Taketomo, FUJINO Toshiyuki, HASEGAWA Hideki
8th International Conference on Atomically Controlled Surfaces Interfaces and Nanostructures, 19 Jan. 2005, English
[International presentation]

Growth of GaN Based Quantum Wire Arrays and Networks by RF Radical Assisted Selective Molecular Beam Epitaxy　　　　　　　　　　　　　　　
SATO Taketomo, OIKAWA Takeshi, HASEGAWA Hideki
The 5th International Conference on Low Dimensional Structures and Devices (LDSD2004), 12 Dec. 2004, English
[International presentation]

Hexagonal BDD Quantum Circuit Architecture for Intelligent Quantum (IQ) Chips　　　　　　　　　　　　　　　
HASEGAWA Hideki, KASAI Seiya, YUMOTO Miki, SATO Taketomo
11th Advanced Heterostructure Workshop, 05 Dec. 2004, English
[International presentation]

Selective MBE Growth of High-Density Hexagonal Nanowire Networks on Pre-Patterned GaAs (001) and (111)B Substrates International Symposium on Nanoscale Devices and Materials　　　　　　　　　　　　　　　
TAMAI Isao, SATO Taketomo, HASHIZUME Tamotsu, HASEGAWA Hideki
206th Meeting of ECS, 03 Oct. 2004, English
[International presentation]

Design and Implementation of Ultra-Small and Ultra-Low-Power Digital Systems Utilizing A Hexagonal BDD Quantum Circuits on GaAs-based Hexagonal Nanowire Network Structures　　　　　　　　　　　　　　　
KASAI Seiya, YUMOTO Miki TAMURA Takahiro, TAMAI Isao, SATO Taketomo, HASEGAWA Hideki
International Symposium on Nanoscale Devices and Materials:206th Meeting of ECS, 03 Oct. 2004, English
[International presentation]

Molecular Beam Epitaxial Growth of GaAs- and GaN-Based Quantum Wire Arrays and Networks on Pre-Patterned Substrates　　　　　　　　　　　　　　　
SATO Taketomo, TAMAI Isao, OIKAWA Takeshi, HASEGAWA Hideki
7th China-Japan Symposium on Thin Films (CJSTF-7), 20 Sep. 2004, English
[International presentation]

Growth of AlGaN/GaN Quantum Wire Structures by RF-Radical Assisted MBE on Pre-Patterned Substrates　　　　　　　　　　　　　　　
SATO Taketomo, OIKAWA Takeshi, HASHIZUME Tamotsu, HASEGAWA Hideki
International Conference on Solid State Devices and Materials 2004, 14 Sep. 2004, English
[International presentation]

Cross-sectional Evolution and Its Mechanism during Selective MBE Growth of GaAs Quantum Wires on (111)B Substrates　　　　　　　　　　　　　　　
TAMAI Isao, SATO Taketomo, HASEGAWA Hideki
International Conference on Solid State Devices and Materials 2004, 14 Sep. 2004, English
[International presentation]

Investigation of Current and Potential Control Characteristics by Nanosized Schottky Gate on AlGaAs/GaAs Surfaces　　　　　　　　　　　　　　　
JIA Rui, SATO Taketomo, KASAI Seiya, HASEGAWA Hideki
31st International Symposium on Compound Semiconductors, 12 Sep. 2004, English
[International presentation]

Investigation of Current and Potential Control Characteristics by Nanosized Schottky Gate on AlGaAs/GaAs Surfaces　　　　　　　　　　　　　　　
SATO TaketomoJia Rui, Sato Taketomo, Kasai Seiya, Hasegawa Hideki
応用物理学会学術講演会講演予稿集, 01 Sep. 2004, English
[Domestic Conference]

GaAs(111)B加工基板へのMBE選択成長法による量子細線の形成とその形成メカニズム
玉井功, 佐藤威友, 長谷川英機
応用物理学会学術講演会講演予稿集, 01 Sep. 2004, Japanese
[Domestic Conference]

MBE選択成長法によるInP(111)B基板上へのInGaAs量子細線ネットワークの形成
木村健, 佐藤威友, 長谷川英機
応用物理学会学術講演会講演予稿集, 01 Sep. 2004, Japanese
[Domestic Conference]

Si界面制御層を用いたGaAs/AlGaAs量子細線の表面パッシベーション
塩崎奈々子, 佐藤威友, 橋詰保, 長谷川英機
応用物理学会学術講演会講演予稿集, 01 Sep. 2004, Japanese
[Domestic Conference]

ECRドライエッチングとMBE選択成長法による加工基板上へのAlGaN/GaNナノ構造の作製と評価
及川武, 佐藤威友, 橋詰保, 長谷川英機
応用物理学会学術講演会講演予稿集, 01 Sep. 2004, Japanese
[Domestic Conference]

MBE選択成長を用いたGaAs BDD量子節点デバイスの試作と性能評価
田村隆博, 湯元美樹, 玉井功, 佐藤威友, 葛西誠也, 長谷川英機
応用物理学会学術講演会講演予稿集, 01 Sep. 2004, Japanese
[Domestic Conference]

RFラジカル支援MBE法によるGaN(0001)加工基板へのGaN/AlGaNヘテロ構造の成長
佐藤威友, 及川武, 橋詰保, 長谷川英機
応用物理学会学術講演会講演予稿集, 01 Sep. 2004, Japanese
[Domestic Conference]

Selective MBE Growth of GaAs Hexagonal Nano-wire Network on Pre-patterned Substrates　　　　　　　　　　　　　　　
TAMAI Isao, SATO Taketomo, HASEGAWA Hideki
Hokkaido Univ. and Seoul National Univ. Joint Symposium, 08 Jul. 2004, English
[International presentation]

Growth Mechanism of GaAs Ridge Quantum Wires on Patterned Substrates　　　　　　　　　　　　　　　
SATO Taketomo, TAMAI Isao, HASEGAWA Hideki
Hokkaido Univ. and Seoul National Univ. Joint Symposium, 08 Jul. 2004, English
[International presentation]

Sidegating Effect Study in AlGaAs/GaAs Quantum Wire Transistors　　　　　　　　　　　　　　　
JIA Rui, KASAI Seiya, SATO Taketomo, HASEGAWA Hideki
Hokkaido Univ. and Seoul National Univ. Joint Symposium, 08 Jul. 2004, English
[International presentation]

GaAs BDD Quantum Node Switches Fabricated on Selectively MBE Grown Quantum Wire Networks　　　　　　　　　　　　　　　
TAMURA Takahiro, YUMOTO Miki, KASAI Seiya, SATO Taketomo, HASEGAWA Hideki
46th Electronic Materials Conference (EMC2004), 23 Jun. 2004, English
[International presentation]

Controlled growth of GaAs ridge quantum wire network by selective MBE and its application to hexagonal BDD quantum logic circuits　　　　　　　　　　　　　　　
HASEGAWA Hideki, SATO Taketomo, TAMURA Takahiro, TAMAI Isao, YUMOTO Miki
12th Int. Symposium on Nanostructures Physics and Technology, 21 Jun. 2004, English
[International presentation]

Surface-related reduction of photoluminescence from GaAs quantum wires and effects of surface passivation using Si interface control layer　　　　　　　　　　　　　　　
SHIOZAKI Nanako, ANANTATHANASARN Sanguan, SATO Taketomo, HASHIZUME Tamotsu, HASEGAWA Hideki
The 12th International Conference on Solid Films and Surfaces, 21 Jun. 2004, English
[International presentation]

Study on ECR dry etching and selective MBE growth of AlGaN/GaN for fabrication of quantum nanostructures on GaN(0001) substrates　　　　　　　　　　　　　　　
OIKAWA Takeshi, ISHIKAWA Fumitaro, SATO Taketomo, HASHIZUME Tamotsu, HASEGAWA Hideki
The 12th International Conference on Solid Films and Surfaces, 21 Jun. 2004, English
[International presentation]

MBE選択成長を用いたGaAs量子細線スイッチの作製と評価
田村隆博, 湯元美樹, 玉井功, 佐藤威友, 葛西誠也, 長谷川英機
応用物理学関係連合講演会講演予稿集, 28 Mar. 2004, Japanese
[Domestic Conference]

加工基板を用いたMBE選択成長法によるGaAsリッジ細線の形成メカニズム
佐藤威友, 玉井功, 長谷川英機
応用物理学関係連合講演会講演予稿集, 28 Mar. 2004, Japanese
[Domestic Conference]

MBE選択成長法による高密度GaAsヘキサゴナル細線ネットワークの形成(2)
玉井功, 吉田崇一, 佐藤威友, 長谷川英機
応用物理学関係連合講演会講演予稿集, 28 Mar. 2004, Japanese
[Domestic Conference]

MBE選択成長による(111)B加工基板上への高密度GaAs量子細線ネットワークの作製と評価
吉田崇一, 玉井功, 佐藤威友, 長谷川英機
応用物理学関係連合講演会講演予稿集, 28 Mar. 2004, Japanese
[Domestic Conference]

内部交差量子細線構造の深さ分解/面内分布カソードルミネッセンス評価
石川史太郎, 及川武, 玉井功, 佐藤威友, 長谷川英機
応用物理学関係連合講演会講演予稿集, 28 Mar. 2004, Japanese
[Domestic Conference]

Growth Kinetics and Modeling of Selective Molecular Beam Epitaxial Growth of GaAs Ridge Quantum Wires on Pre-Patterned Substrates　　　　　　　　　　　　　　　
SATO Taketomo, TAMAI Isao, HASEGAWA Hideki
2004 International Seminar for 21st Century COE Program: Quantum Nanoelectronics for Meme-Media-Based Infromation Technology (II), 09 Feb. 2004, English
[International presentation]

Mechanism of Selective Growth of GaAs Ridge Quantum Wires on Non-planar Substrates during Molecular Beam Epitaxy　　　　　　　　　　　　　　　
SATO Taketomo, TAMAI Isao, HASEGAWA Hideki
31st Conference on the Physics and Chemistry of Semiconductor Interfaces, 18 Jan. 2004, English
[International presentation]

Prospects of III-V quantum LSIs based on hexagonal BDD approach　　　　　　　　　　　　　　　
KASAI Seiya, SATO Taketomo, HASEGAWA Hideki
10 Dec. 2003, English
[Invited], [International presentation]

Selective MBE Growth of GaAs Hexagonal Nano-wire Networks on (111)B Patterned Substrates　　　　　　　　　　　　　　　
YOSHIDA Souichi, TAMAI Isao, SATO Taketomo, HASEGAWA Hideki
International Conference on Solid State Devices and Materials, 16 Sep. 2003, English
[International presentation]

Control of Heterointerface Cross-Sections of GaAs Ridge Quantum Wires by Selective Molecular Beam Epitaxy　　　　　　　　　　　　　　　
SATO Taketomo, TAMAI Isao, YOSHIDA Souichi, HASEGAWA Hideki
The 9th International Conference on the Formation of Semiconductor Interfaces (ICFSI-9), 15 Sep. 2003, English
[International presentation]

MBE選択成長法を用いた高密度GaAsヘキサゴナル細線ネットワークの形成
玉井功, 吉田崇一, 佐藤威友, 長谷川英機
応用物理学会学術講演会講演予稿集, 30 Aug. 2003, Japanese
[Domestic Conference]

(111)B加工基板上へのMBE選択成長によるGaAs量子細線ネットワークの形成
吉田崇一, 玉井功, 佐藤威友, 長谷川英機
応用物理学会学術講演会講演予稿集, 30 Aug. 2003, Japanese
[Domestic Conference]

GaAs加工基板上へのMBE選択成長法によるGaAs/AlGaAsリッジ細線の形成メカニズム
佐藤威友, 玉井功, 吉田崇一, 長谷川英機
応用物理学会学術講演会講演予稿集, 30 Aug. 2003, Japanese
[Domestic Conference]

Formation of High Density GaAs Hexagonal Nanowire Networks by Selective MBE Growth on Pre-patterned (001) Substrates　　　　　　　　　　　　　　　
TAMAI Isao, SATO Taketomo, HASEGAWA Hideki
11th International Conference on Modulated Semiconductor Structures (MSS11), 14 Jul. 2003, English
[International presentation]

Kinetic Evolution of Facet Boundary Planes during Growth of III-V Ridge Quantum Wire Arrays by Selective Molecular Beam Epitaxy　　　　　　　　　　　　　　　
HASEGAWA Hideki, SATO Taketomo, JIANG Chao, MURANAKA Tsutomu
Symposium on Surface Science 2003 (3S03), 30 Mar. 2003, English
[International presentation]

MBE選択成長法を用いたGaAs/AlGaAsヘキサゴナル細線ネットワークの形成とその評価 (2)
玉井功, 吉田崇一, 佐藤威友, 長谷川英機
応用物理学関係連合講演会講演予稿集, 27 Mar. 2003, Japanese
[Domestic Conference]

MBE選択成長法によるGaAs(111)B加工基板上へのGaAs系量子構造の作製と評価
吉田崇一, 玉井功, 佐藤威友, 長谷川英機
応用物理学関係連合講演会講演予稿集, 27 Mar. 2003, Japanese
[Domestic Conference]

加工基板を用いたMBE選択成長によるGaAs/AlGaAsリッジ細線の形成とデバイス応用
佐藤威友, 玉井功, 長谷川英機
応用物理学関係連合講演会講演予稿集, 27 Mar. 2003, Japanese
[Domestic Conference]

Selective MBE Growth of GaAs Ridge Quantum Wires for Formation of Hexagonal Nanowire Networks　　　　　　　　　　　　　　　
SATO Taketomo, TAMAI Isao, HASEGAWA Hideki
2003 RCIQE International Seminar on Quantum Nanoelectronics for Meme-Media-Based Information Technologies, 12 Feb. 2003, English
[International presentation]

Selective MBE Growth of GaAs Ridge Quantum Wire Arrays on Patterned (001) Substrates and Its Growth Mechanism　　　　　　　　　　　　　　　
SATO Taketomo, TAMAI Isao, HASEGAWA Hideki
29th International Symposium on Compound Semiconductors (ISCS2002), 07 Oct. 2002, English
[International presentation]

GaAs上に形成したナノショットキーゲート電極のポテンシャル制御特性 (2)
亀田篤志, 葛西誠也, 佐藤威友, 長谷川英機
応用物理学会学術講演会講演予稿集, 24 Sep. 2002, Japanese
[Domestic Conference]

加工基板を用いたMBE選択成長法によるGaAs/AlGaAs量子細線の形成と評価 (2)
佐藤威友, 玉井功, 長谷川英機
応用物理学会学術講演会講演予稿集, 24 Sep. 2002, Japanese
[Domestic Conference]

MBE選択成長法を用いたGaAs/AlGaAsヘキサゴナル細線ネットワークの形成とその評価
玉井功, 吉田崇一, 佐藤威友, 長谷川英機
応用物理学会学術講演会講演予稿集, 24 Sep. 2002, Japanese
[Domestic Conference]

Selective MBE Growth of <-110> and <510>-Oriented GaAs Ridge Quantum Wires on Patterned (001) Substrates for Formation of Hexagonal Nanowire Networks　　　　　　　　　　　　　　　
SATO Taketomo, TAMAI Isao, HASEGAWA Hideki
The Second International Workshop on Quantum Nonplanar Nanostructures & Nanoelectronics (QNN02), 09 Sep. 2002, English
[International presentation]

Mechanism and Suppression of Anomalously Large Reverse Leakage Currents in n-type GaN Schottky Contacts　　　　　　　　　　　　　　　
SATO Taketomo, OYAMA Susumu, HASEGAWA Hideki
26th International Conference on the Physics of Semiconductors, 29 Jul. 2002, English
[International presentation]

Selective MBE Growth of High Density GaAs/AlGaAs Hexagonal Nanowire Network Structures on Pre-Patterned GaAs Substrates　　　　　　　　　　　　　　　
TAMAI Isao, SATO Taketomo, HASEGAWA Hideki
2002 Electronic Materials Conference, 26 Jun. 2002, English
[International presentation]

Understanding and Control of Current Transport in GaN Schottky Contacts with Large Reverse Leakage Currents　　　　　　　　　　　　　　　
HASEGAWA Hideki, SATO Taketomo, OYAMA Susumu
26th Workshop on Compound Semiconductor Devices and Integrated Circuits held in Europe (WOCSDICE), 21 May 2002, English
[International presentation]

MBE選択成長法により形成したGaAs/AlGaAs結合量子細線構造の評価
玉井功, 佐藤威友, 長谷川英機
応用物理学関係連合講演会講演予稿集, 27 Mar. 2002, Japanese
[Domestic Conference]

GaAs上に形成したナノショットキーゲート電極のポテンシャル制御特性
亀田篤志, 葛西誠也, 佐藤威友, 長谷川英機
応用物理学関係連合講演会講演予稿集, 27 Mar. 2002, Japanese
[Domestic Conference]

電気化学プロセスによるInPポーラス構造の形成とその応用 (3)
平野哲郎, 佐藤威友, 長谷川英機
応用物理学関係連合講演会講演予稿集, 27 Mar. 2002, Japanese
[Domestic Conference]

加工基板を用いたMBE選択成長法によるGaAs/AlGaAs量子細線の形成と評価
佐藤威友, 玉井功, 長谷川英機
応用物理学関係連合講演会講演予稿集, 27 Mar. 2002, Japanese
[Domestic Conference]

電気化学プロセスによるInPポーラス構造の形成とその応用(2)
平野哲郎, 佐藤威友, 伊藤章, 石川史太郎, 長谷川英機
応用物理学会学術講演会講演予稿集, 11 Sep. 2001, Japanese
[Domestic Conference]

加工基板を用いたMBE選択成長法によるGaAsリッジ構造の形成と評価
佐藤威友, 玉井功, 長谷川英機
応用物理学会学術講演会講演予稿集, 11 Sep. 2001, Japanese
[Domestic Conference]

電気化学プロセスによるInPポーラス構造の形成とその応用
平野哲郎, 佐藤威友, 伊藤章, 石川史太郎, 長谷川英機
応用物理学関係連合講演会講演予稿集, 28 Mar. 2001, Japanese
[Domestic Conference]

化合物半導体ナノショットキー接触界面の電気的特性とその制御(2)
佐藤威友, 亀田篤志, 葛西誠也, 長谷川英機
応用物理学関係連合講演会講演予稿集, 28 Mar. 2001, Japanese
[Domestic Conference]

Effects of Surface Fermi Level Pinning and Surface State Charging on Control Characteristics of Nanometer Scale Schottky Gates Formed on GaAs　　　　　　　　　　　　　　　
KAMEDA Atsuchi, KASAI Seiya, SATO Taketomo, HASEGAWA Hideki
2001 International Semiconductor Device Research Symposium (ISDRS2001), 2001, English
[International presentation]

Selective MBE Growth of GaAs/AlGaAs Hexagonal Nanowire Network Structures on (001) Patterned GaAs Substrates　　　　　　　　　　　　　　　
SATO Taketomo, TAMAI Isao, JIANG Chao, HASEGAWA Hideki
28th International Symposium on Compound Semiconductors (ISCS2001), 2001, English
[International presentation]

Electrochemical Formation of Self-Assembled Nanopore Arrays As Templates for MBE Growth of InP-based Quantum Wires and Dots　　　　　　　　　　　　　　　
HIRANO Tetsuro, ITO Akira, SATO Taketomo, ISHIKAWA Fumitaro, HASEGAWA Hideki
2001 International Conference on Indium Phosphide and Related Materials (IPRM2001), 2001, English
[International presentation]

微小金属ドットを有する化合物半導体単電子デバイス構造(5)
岡田浩, 佐藤威友, 長谷川英機
応用物理学会学術講演会講演予稿集, 03 Sep. 2000, Japanese
[Domestic Conference]

化合物半導体ナノショットキー接触界面の電気的特性とその制御
佐藤威友, 葛西誠也, 長谷川英機
応用物理学会学術講演会講演予稿集, 03 Sep. 2000, Japanese
[Domestic Conference]

微小金属ドットを有する化合物半導体単電子デバイス構造(4)
岡田浩, 佐藤威友, 長谷川英機
応用物理学関係連合講演会講演予稿集, 28 Mar. 2000, Japanese
[Domestic Conference]

電気化学プロセスを用いて作製した化合物半導体ナノショットキー接触の電気的特性
佐藤威友, 葛西誠也, 岡田浩, 長谷川英機
応用物理学関係連合講演会講演予稿集, 28 Mar. 2000, Japanese
[Domestic Conference]

Electrical Properties of Nanometer-Sized Schottky Contacts for Gate Control of III-V Single Electron Devices　　　　　　　　　　　　　　　
SATO Taketomo, KASAI Seiya, HASEGAWA Hideki
International Symposium on Formation Physics and Device Application of Quantum Dot Structures, 2000, English
[International presentation]

Current Transport and Capacitance-Voltage Characteristics of GaAs and InP Nanometer-Sized Schottky Contacts Formed by in situ Electrochemical Process　　　　　　　　　　　　　　　
SATO Taketomo, KASAI Seiya, HASEGAWA Hideki
10 th International Conference on Solid Films and Surfaces, 2000, English
[International presentation]

Formation and Characterization of Nanometer-Sized Schottky Contacts on III-V Materials by In-SItu Electrochemical Process　　　　　　　　　　　　　　　
SATO Taketomo, KASAI Seiya, HASEGAWA Hideki
42nd Electronic Materials Conference, 2000, English
[International presentation]

Self-Assembled Formation of InP Nanopore Arrays by Electrochemical Anodization　　　　　　　　　　　　　　　
FUJIKURA Hajime, LIU Aimin, SATO Taketomo, HIRANO Tetsuro, HASEGAWA Hideki
2000 International Conference on Indium Phosphide and Related Materials (IPRM2000), 2000, English
[International presentation]

ナノショットキー接触の電気的特性
佐藤威友, 葛西誠也, 岡田浩, 長谷川英機
電気関係学会北海道支部連合大会講演論文集, 23 Oct. 1999, Japanese
[Domestic Conference]

微小金属ドットを有する化合物半導体単電子デバイス構造 (3)
岡田浩, 佐藤威友, 長谷川英機
応用物理学会学術講演会講演予稿集, 01 Sep. 1999, Japanese
[Domestic Conference]

電気化学プロセスを用いて作製したナノショットキー接触の電気的特性
佐藤威友, 葛西誠也, 岡田浩, 長谷川英機
応用物理学会学術講演会講演予稿集, 01 Sep. 1999, Japanese
[Domestic Conference]

微小金属ドットを有する化合物半導体単電子デバイス構造 (2)
岡田浩, 佐藤威友, 長谷川英機
応用物理学関係連合講演会講演予稿集, 28 Mar. 1999, Japanese
[Domestic Conference]

電気化学プロセスを用いたInP系材料に対するナノショットキー接触の形成
佐藤威友, 岡田浩, 長谷川英樹
応用物理学関係連合講演会講演予稿集, 28 Mar. 1999, Japanese
[Domestic Conference]

電気科学プロセスによるIII‐V族化合物半導体表面・ショットキー界面の制御
橋詰保, 兼城千波, 佐藤威友, 長谷川英機
電気化学会大会講演要旨集, 24 Mar. 1999, Japanese
[Domestic Conference]

Properties of nanometer-sized metal contacts on GaAs, InP and their related materials　　　　　　　　　　　　　　　
HASEGAWA Hideki, SATO Taketomo, KASAI Seiya
Surfaces and Interfaces of Mesoscopic Devices, 1999, English
[International presentation]

Electrochemical Formation of Nanometer-Sized Straight Pore Arrays on (001) InP Surfaces　　　　　　　　　　　　　　　
LIU Aimin, HAMAMATSU Akihito, SATO Taketomo, FUJIKURA Hajime, HASEGAWA Hideki
International Symposium on Surface Science for Micro- and Nano-Device Fabrication, 1999, English
[International presentation]

Electrical Properties of Nanometer-Sized Schottky Contacts on n-GaAs and n-InP Formed by in situ Electrochemical Process　　　　　　　　　　　　　　　
SATO Taketomo, KASAI Seiya, OKADA Hiroshi, HASEGAWA Hideki
International Symposium on Surface Science for Micro- and Nano-Device Fabrication, 1999, English
[International presentation]

Unpinning of Fermi Level in Nanometer-Sized Schottky Contacts on GaAs and InP　　　　　　　　　　　　　　　
HASEGAWA Hideki, SATO Taketomo
7th International Conference on Formation of Semiconductor Interfaces, 1999, English
[International presentation]

Subnano-Scale Selective Etching and Nano-Scale Pore Array Formation on InP (001) Surfaces by a Wet Electrochemical Process　　　　　　　　　　　　　　　
HAMAMATSU Akihito, KANESHIRO Chinami, SATO Taketomo, FUJIKURA Hajime, HASEGAWA Hideki
International Conference on 1999 Indium Phosphide and Related Materials (IPRM99), 1999, English
[International presentation]

Formation on Nanometer-Sized Schottky Contacts on InP and Related Materials by in situ Electrochemical Process　　　　　　　　　　　　　　　
SATO Taketomo, OKADA Hiroshi, HASEGAWA Hideki
11th International Conference on Indium Phosphide and Related Materials (IPRM99), 1999, English
[International presentation]

Formation of Fermi Level Pinning Free Nano-scale Schottky Contacts on Compound Semiconductor and Their Application to Single Electron Devices　　　　　　　　　　　　　　　
HASEGAWA Hideki, SATO Taketomo, OKADA Hiroshi
Symposium on Surface Physics, 1999, English
[International presentation]

Compound semiconductor single electron device structures having nano-metal dots.
OKADA HIROSHI, SATO TAKETOMO, KANESHIRO CHINAMI, JINUSHI KEIICHIRO, HASEGAWA HIDEKI
応用物理学会学術講演会講演予稿集, Sep. 1998, Japanese
[Domestic Conference]

Formation of porous InP by anodization.
HAMAMATSU AKIHITO, SATO TAKETOMO, KANESHIRO CHINAMI, FUJIKURA HAJIME, HASEGAWA HIDEKI
応用物理学会学術講演会講演予稿集, Sep. 1998, Japanese
[Domestic Conference]

Electrochemical etching of n-InP surface in an acid solution.
KANESHIRO CHINAMI, SATO TAKETOMO, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
応用物理学会学術講演会講演予稿集, Sep. 1998, Japanese
[Domestic Conference]

Formation of metal particles and its application to metal/semiconductor nano-structure by erectrochemical process.
SATO TAKETOMO, OKADA HIROSHI, KANESHIRO CHINAMI, HASEGAWA HIDEKI
応用物理学会学術講演会講演予稿集, Sep. 1998, Japanese
[Domestic Conference]

Formation and characterization of metal nano-grain array by electrochemical process.
SATO TAKETOMO, OKADA HIROSHI, KANESHIRO CHINAMI, HASEGAWA HIDEKI
応用物理学関係連合講演会講演予稿集, Mar. 1998, Japanese
[Domestic Conference]

Schottky barrier hights for a range of metals deposited on n-GaAs sureface by using electrochemical process.
KANESHIRO CHINAMI, SATO TAKETOMO, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
応用物理学関係連合講演会講演予稿集, Mar. 1998, Japanese
[Domestic Conference]

Photo-voltaic characterization of Pt-dots/InP surfaces in electrolytic solutions.
HAMAMATSU AKIHITO, KANESHIRO CHINAMI, SATO TAKETOMO, HASEGAWA HIDEKI
応用物理学関係連合講演会講演予稿集, Mar. 1998, Japanese
[Domestic Conference]

Formation and control of Schottky contacts formed by in situ electrochemical process.
SATO TAKETOMO, KANESHIRO CHINAMI, SOKOLOV D V, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
応用物理学関係連合講演会講演予稿集, Mar. 1998, Japanese
[Domestic Conference]

Properties of Nanometer-Sized Metal-Semiconductor Interfaces of GaAs, InP and GaN Formed by An In-Situ Electrochemical Process　　　　　　　　　　　　　　　
HASEGAWA Hideki, SATO Taketomo, KANESHIRO Chinami, KOYAMA Yuuji
1999 International Conference on Physics and Chemistry of Semiconductor Interfaces, 1998, English
[International presentation]

Realization of Strongly Metal-Dependent Schottky Barrier Heights on n-GaAs by In Situ Electrochemical Process　　　　　　　　　　　　　　　
KANESHIRO Chinami, SATO Taketomo, HASHIZUME Tamotsu, HASEGAWA Hideki
25th International Symposium on Compound Semiconductors, 1998, English
[International presentation]

Surface Modification of InP By Photoelectrohcemical Process　　　　　　　　　　　　　　　
HAMAMATSU Akihito, KANESHIRO Chinami, SATO Taketomo, FUJIKURA Hajime, HASEGAWA Hideki
International Symposium on Electrochemistry of Ordered Interfaces, 1998, English
[International presentation]

Formation of Size- and Position-Controlled Nanometer Size Pt Dots on GaAs and InP Substrates by Pulsed Electrochemical Deposition　　　　　　　　　　　　　　　
SATO Taketomo, KANESHIRO Chinami, OKADA Hiroshi, HASEGAWA Hideki
International Conference on Solid State Devices and Materials, 1998, English
[International presentation]

Fabrication of Regular Arays of Nanometer-Sized Pt Dots on III-V Substrates by Electron Beam Lithography and Electrochemical Deposition　　　　　　　　　　　　　　　
SATO Taketomo, KANESHIRO Chinami, OKADA Hiroshi, HASEGAWA Hideki
40th Electronic Matterials Conference (EMC'98), 1998, English
[International presentation]

Highly Controllable Electrochemical Etching of InP studied by Voltammetry and Scanned Probe Microscope　　　　　　　　　　　　　　　
KANESHIRO Chinami, SATO Taketomo, HASEGAWA Hideki
10th International Conference on Indium Phosphide and Related Materials (IPRM98), 1998, English
[International presentation]

Strong Correlation Between Interface Microstructure and Barrier Height in n-InP Schottky Contacts Formed by In Situ Electrochemical Process　　　　　　　　　　　　　　　
SATO Taketomo, KANESHIRO Chinami, HASEGAWA Hideki
10th International Conference on Indium Phosphide and Related Materials (IPRM98), 1998, English
[International presentation]

Formation of Pt Dot Array by erectrochemical process.
SATO TAKETOMO, OKADA HIROSHI, KANESHIRO CHINAMI, HASEGAWA HIDEKI
電気関係学会北海道支部連合大会講演論文集, 1998, Japanese
[Domestic Conference]

In Situ STM obsersvation of InP surface in an solution.
KANESHIRO CHINAMI, SATO TAKATOMO, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
応用物理学会学術講演会講演予稿集, Oct. 1997, Japanese
[Domestic Conference]

Photo-voltac characterization of Schottky contacts on InP-based materials.
HAMAMATSU AKIHITO, SATO TAKETOMO, KANESHIRO CHINAMI, SAITO TOSHIYA, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
応用物理学会学術講演会講演予稿集, Oct. 1997, Japanese
[Domestic Conference]

Fomation and control of Schottky contacts formed by in situ electrochemical process.
SATO TAKATOMO, KANESHIRO CHINAMI, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
応用物理学会学術講演会講演予稿集, Oct. 1997, Japanese
[Domestic Conference]

Schottky Barrier Formation to Compound Semiconductors by in-situ Electrochemical Process and Its Controllability.
SATO TAKETOMO, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
電気化学秋季大会講演要旨集, Aug. 1997, Japanese
[Domestic Conference]

Preparation of sputter-deposited Pt/InP interfaces.
NOYA ATSUSHI, TAKEYAMA MAYUMI, SATO TAKETOMO, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
応用物理学関係連合講演会講演予稿集, Mar. 1997, Japanese
[Domestic Conference]

Formation of Schottky contacts to InP-based materials by in-situ electrochemical process.
SATO TAKETOMO, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
応用物理学関係連合講演会講演予稿集, Mar. 1997, Japanese
[Domestic Conference]

Formation of Pinning-Free Schottky Barriers on InP and Related Materials by Novel In-Situ Electrochemical Process and Its Mechanism　　　　　　　　　　　　　　　
SATO Taketomo, HASEGAWA Hideki
9th International Conference on Indium Phosphide and Related Materials (IPRM97), 1997, English
[International presentation]

Evolution of Nearly Pinning-Free Metal-Semiconductor Interfaces on InP and Related Materials by Novel In-Situ Electrochemical Process　　　　　　　　　　　　　　　
SATO Taketomo, HASHIZUME Tamotsu, HASEGAWA Hideki
1997 International Conference on Physics and Chemistry of Semiconductor Interfaces, 1997, English
[International presentation]

In situ observation of InP surface in acid solutions by EC STM.
KANESHIRO CHINAMI, SATO TAKETOMO, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
電気関係学会北海道支部連合大会講演論文集, 1997, Japanese
[Domestic Conference]

Formation of Schottky contacts by in situ electrochemical process.
SATO TAKETOMO, KANESHIRO CHINAMI, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
電気関係学会北海道支部連合大会講演論文集, 1997, Japanese
[Domestic Conference]

Formation of Schottky contacts with high Schottky barrier heights to InP-based materials and its mechanism.
SATO TAKETOMO, UNO SHOICHI, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
応用物理学会学術講演会講演予稿集, Sep. 1996, Japanese
[Domestic Conference]

Formation of Schottky barriers to InP based materials by In Situ electrochemical process.
UNO SHOICHI, SATO TAKETOMO, KASAI SEIYA, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
応用物理学関係連合講演会講演予稿集, Mar. 1996, Japanese
[Domestic Conference]

Enhancement of Schottky Barrier Heights on Indium Phosphide-Based Materials by In-Situ Electrochemical Process and Its Mechanism　　　　　　　　　　　　　　　
SATO Taketomo, UNO Shouichi, HASHIZUME Tamotsu, HASEGAWA Hideki
International Conference on Solid State Devices and Materials, 1996, English
[International presentation]

Fabrication of high-performance InP MESFETs with in-situ pulse-plated metal gates　　　　　　　　　　　　　　　
UNO Shouichi, Tamotsu Hashizme, SATO Taketomo, FUJIKURA Hajime, HASEGAWA Hideki
International Conference on Indium Phosphide and Related Materials (IPRM96), 1996, English
[International presentation]

Formation of high Schottky barrier heights to InP-based materials by in-situ electrochemical process and its mechanism.
SATO TAKETOMO, HASHIZUME TAMOTSU, HASEGAWA HIDEKI
電気関係学会北海道支部連合大会講演論文集, 1996, Japanese
[Domestic Conference]

自然科学実験（物理学）　　　　　　　　　　　　　　　
北海道大学 全学

電気電子工学実験基礎　　　　　　　　　　　　　　　
北海道大学 工学部

情報エレクトロニクス特別演習　　　　　　　　　　　　　　　
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機能デバイス学特論　　　　　　　　　　　　　　　
北海道大学 情報科学研究科

電子工学演習　　　　　　　　　　　　　　　
北海道大学 工学部

電子工学実験　　　　　　　　　　　　　　　
北海道大学 工学部

量子力学　　　　　　　　　　　　　　　
北海道大学 工学部

国際交流科目”Forefront of Semiconductor Electronics”　　　　　　　　　　　　　　　
北海道大学 全学

情報学　　　　　　　　　　　　　　　
北海道大学 全学

科学技術の世界「半導体エレクトロニクスの最前線」　　　　　　　　　　　　　　　
北海道大学 全学

電子情報工学実験　　　　　　　　　　　　　　　
北海道大学 工学部

応用数学1　　　　　　　　　　　　　　　
北海道大学 工学部

先端デバイス学特論　　　　　　　　　　　　　　　
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応用デバイス回路学特論　　　　　　　　　　　　　　　
北海道大学 情報科学研究科

集積回路工学　　　　　　　　　　　　　　　
北海道大学 工学部

電子情報工学実験 テキストの作成・更新　　　　　　　　　　　　　　　
佐藤 威友, [Educational materials]

量子集積エレクトロニクス研究センター ホームページの更新　　　　　　　　　　　　　　　
佐藤 威友, [Web service]

窒化物半導体異種界面パラレル伝導制御とマルチチャネル高周波トランジスタの開発
科学研究費助成事業
01 Apr. 2023 - 31 Mar. 2026
佐藤 威友, 三好 実人, 赤澤 正道
日本学術振興会, 基盤研究(B), 北海道大学, 23H01437

超ワイドギャップAlN系半導体を用いたパワートランジスタの開発
科学研究費助成事業 基盤研究(B)
01 Apr. 2021 - 31 Mar. 2024
三好 実人, 佐藤 威友
窒化アルミニウム(AlN)は、GaNの3.4eV、SiCの3.2eVを大きく上回る6.2eVという極めて大きなバンドギャップエネルギーを持つ究極的なパワーデバイス用半導体材料である。AlNの絶縁破壊電界は非常に高く、パワーデバイスとして利用した場合のOFF耐圧はGaNやSiCの約10倍にもなると予想されている。一方、AlNは、化学的安定性が高く機械的強度・硬度に優れることも大きな特徴となっているが、これらの諸物性は機能デバイスへの応用を考えた際の技術的困難さも生じさせている。本研究では、将来社会の省エネ化ニーズに応えるアイテムとして、GaN, SiC以上の超ワイドバンドギャップ半導体である窒化アルミニウム(AlN)系ヘテロ構造をベースとしたパワートランジスタを着想、その実現に向けた課題と方策を以下のように設定し、研究計画を策定した。
(1) AlN系ヘテロ構造のエピタキシャル成長技術確立： 目標のトランジスタ構造を実現するために表面平坦で且つ所望の電気特性を示すAlN系ヘテロ構造のエピタキシャル成長技術を確立する。
(2) AlN系トランジスタのデバイス化技術構築： デバイス化にあたってのキーとなるオーミック電極形成、およびノーマリOFF動作のための精密微細加工に係るプロセス技術を構築する。
(3) AlN系トランジスタの試作と到達性能の確認： 上記2項目に対応したうえでデバイス試作と評価を進め、理想デバイスの設計と到達性能の理論推定を行う。以上のような学理的なアプローチを以て、AlN系トランジスタが既存品を超えて真に将来有望なデバイスとなり得るかを検証する。
日本学術振興会, 基盤研究(B), 名古屋工業大学, 21H01389

Development of wet etching technology for nitride semiconductors using strong oxidizing agents and application to transistors
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
01 Apr. 2020 - 31 Mar. 2023
佐藤 威友, 三好 実人, 橋詰 保
(1)硫酸ラジカル（SO4*-）を使った窒化物半導体混晶（AlGaN）のエッチング
前年度に得られた知見を基に、窒化アルミニウムガリウム（AlGaN）のウェットエッチングに成功した。UVC照射強度とともに硫酸ラジカル（SO4*-）の生成レートは上昇し、エッチングレートが増大した。また、反応初期では、エッチング深さはUVC照射時間に比例して増大したが、時間の経過とともにエッチング量が飽和し自己停止した。自己停止深さは、試料表面に形成する陰極パッドの材質により大きく変化することを明らかにした。陰極パッドの役割は、UVC照射によって生成した電子-正孔対のうち、エッチング反応に利用されない電子を効率的に反応面から遠ざけることにあり、試料表面との接触抵抗が低い材料を陰極パッドに用いた場合に、エッチングレートが増大することを示した。さらに、開発したウェットエッチング法を、AlGaN/GaNヘテロ構造を利用したヘテロ構造電界効果トランジスタ（HFET）のゲートリセス加工に適用した。AlGaN層内でエッチングを自己停止することにより、同一チップ上に作製したトランジスタの閾値電圧のばらつきを抑えることに成功した。
(2)溶液とp-GaN界面の電気化学的評価
電気化学容量-電圧（ECV）法、電気化学インピーダンス分光（EIS）法により、水溶液／p-GaN界面の電気的特性評価を行った。本測定により得られたp-GaNのアクセプタ密度は、大気中で測定したショットキーダイオードの結果と矛盾なく、設計通りの値を示した。また、溶液中で正の電圧（陽極電圧）を印加すると、p-GaN表面に酸化膜が形成され内蔵電位や周波数応答特性の違いとして検出されることを明らかにした。p-GaNの電気化学エッチング量は、時間や通過電荷量で制御可能であることを示した。
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 20H02175

Interface control of heterojunctions including singularity structures for advanced electron devices
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
30 Jun. 2016 - 31 Mar. 2021
Hashizume Tamotsu
We have investigated interface properties of Schottky and MOS structures with a non-polar m-plane GaN surface and processed GaN surfaces by a plasma-assisted etching, an ion implantation and a high-temperature annealing. The detailed electrical characterization detected various kinds of electronic states created at the GaN surfaces. Then, a chemically stable HfSiOx gate with a high permittivity has been applied to AlGaN/GaN high-electron-mobility transistors (HEMTs), resulting in excellent I-V characteristics with a slight fluctuation of threshold voltage. In addition, a recess-gate GaN MOS HEMT was fabricated using an electrodeless photo-assisted electrochemical etching. The DC characterization showed a precise control of threshold voltage in the I-V characteristics of the recess-gate MOS HEMT.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), Hokkaido University, 16H06421

省エネルギー社会の実現に資する次世代半導体研究開発（パワーデバイス・システム領域）　　　　　　　　　　　　　　　
委託事業-再委託機関
2016 - 2021
文部科学省

社会実装を目指したＧａＮ縦型パワーデバイス作製技術の確立　　　　　　　　　　　　　　　
革新的パワーエレクトロニクス創出基盤技術開発事業（パワーデバイス領域）
2021
文部科学省

GaNの光電気化学エッチングに関する研究　　　　　　　　　　　　　　　
共同研究
2021
株式会社サイオクス, 北海道大学

GaNの光電気化学プロセス　　　　　　　　　　　　　　　
共同研究
2021
三菱電機株式会社, 北海道大学

Low-damage Processing of Nitride Semiconductors Based on Self-stoping Oxdization and Transistor Applications
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
01 Apr. 2017 - 31 Mar. 2020
Sato Taketomo
The photo-electrochemical (PEC) process was developed for fabricating recessed-gate AlGaN/GaN high-electron-mobility transistors (HEMTs). The photo-carriers generated in the top AlGaN layer caused homogeneous etching of AlGaN with a smooth surface. Self-termination phenomena observed under optimal PEC condition were useful for precisely controlling the etching depth in the AlGaN layer. Two types of HEMTs, i.e., Schottky-gate and metal-insulator-semiconductor (MIS)-gate, were fabricated. A recessed-gate AlGaN/GaN structure fabricated with PEC etching showed positive threshold voltage, and its variation was very small. A recessed-gate structure with PEC etching showed better current transport controllability with a small subthreshold-slope than that of planar-gate and dry-etched-gate AlGaN/GaN structures.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 17H03224

Low-damage Processing of Nitride Semiconductors Based on Self-stoping Oxdization and Transistor Applications　　　　　　　　　　　　　　　
Grant-in-Aid for Scientific Research (B)
Apr. 2017 - Mar. 2020
SATO Taketomo
Ministry of Education, Culture, Sports, Science and Technology, Principal investigator, Competitive research funding

GaNの光電気化学エッチングに関する研究　　　　　　　　　　　　　　　
共同研究
2020
株式会社サイオクス, 北海道大学

GaNの光電気化学プロセス　　　　　　　　　　　　　　　
共同研究
2020
三菱電機株式会社, 北海道大学

GaNの光電気化学エッチングに関する研究　　　　　　　　　　　　　　　
共同研究
2019
株式会社サイオクス, 北海道大学

Visible light responsive photocatalysts utilizing nitride semiconductor-based nanostructures for artificial photosynthesis
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
01 Apr. 2015 - 31 Mar. 2018
Taketomo Sato
GaN-based photocatalyst electrodes utilizing electrochemically-formed porous structures have been developed. The precise control of pore diameter and depth has been achieved by optimizing the condition of electrochemical etching and subsequent wet-chemical etching. The decrease of photo reflectance and increase of the effective surface area of GaN porous structures lead to the improvement of the photo-electrochemical conversion efficiency. The functionalization utilizing NiO and Cu2O on n-GaN electrodes was very effective respectively for the improvement of corrosion resistance and the photoelectrochemical conversion in visible light region (400-600nm).
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 15K13937

窒化物半導体周期的ナノ構造を基盤とした可視光応答型光触媒の開発と人工光合成応用　　　　　　　　　　　　　　　
Grant-in-Aid for Challenging Exploratory Research
Apr. 2015 - Mar. 2018
SATO Taketomo
Ministry of Education, Culture, Sports, Science and Technology, Principal investigator, Competitive research funding

III-V族化合物半導体の酸化腐食に関する研究　　　　　　　　　　　　　　　
共同研究
2015 - 2018
オルガノ株式会社, 北海道大学

Nanoscale control of nitride semiconductor surface using low-damaged process for high-sensitive chemical sensors　　　　　　　　　　　　　　　
Grant-in-Aid for Scientific Research (B)
Apr. 2013 - Mar. 2016
SATO Taketomo
Ministry of Education, Culture, Sports, Science and Technology, Principal investigator, Competitive research funding

絶縁膜物性・界面状態のGaNトランジスタの性能と関係性の研究　　　　　　　　　　　　　　　
共同研究
2016 - 2016
住友電気工業株式会社

Nanoscale control of nitride semiconductor surface using low-damaged process for high-sensitive chemical sensors
Grants-in-Aid for Scientific Research
2013 - 2015
SATO Taketomo, HASHIZUME Tamotsu, MOTOHISA Junichi, YATABE Zenji
Towards the higher sensitivity of ion-sensitive field-effect transistors (ISFETs) on nitride semiconductors, the porous-gate ISFETs has been proposed and its basic technology was established. The porous structures with a high-aspect ratio having a several 10 nm-diameter were successfully formed in a controlled fashion utilizing the electrochemical oxidation and etching process. It was found that the unique features of porous structures such as a large surface area and a modified potential involved with a high-electric field are very effective to detect the photo-electrochemical reactions with high-sensitivity. The correlation between the ion-diffusion in the pores and charging and discharging to the double layer were discussed on the basis of the experimental and theoretical results, leading to the new finding for the high-speed and high-sensitive chemical sensors.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, Principal investigator, Competitive research funding, 25289079

GaN HEMTのためのプロセス技術と接合界面評価　　　　　　　　　　　　　　　
共同研究
2012 - 2015
トヨタ自動車株式会社, 北海道大学

Exploration of novel materials for photochemical water splitting based on semiconductor nanowires and nanostructures
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
01 Apr. 2012 - 31 Mar. 2014
MOTOHISA Junichi, SATO Taketomo
To explore novel materials for photochemical water splitting, we attempted the fabrication of GaN-based nanostructuers and their characterization of electrochemical properties. Growth of GaN and InGaN nanostructures were attempted by selective-area growth using RF-plasma-assisted molecular beam epitaxy. Hexagonal pyramidal structures of GaN were successfully fabricated and a use of alternate mask material for selective-area growth was suggested to be important to realized nanowires which is suitable for water splitting. We also investigated the photo-electrochemical properties of GaN by measureing current-voltage characteristics of GaN in electroryte with and without light irradiation. Furthermore, their characteristics was compared with porous structures, which were fabricated by photo-assisted chemial etching and had high-denstiy nanometer-sized pores on the surface, and it was found that porous structures allowed much lager photocurrent as compared to planar structures.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 24656196

Exploration of novel materials for photochemical water splitting based on semiconductor nanowires and nanostructures　　　　　　　　　　　　　　　
Grant-in-Aid for Challenging Exploratory Research
2012 - 2014
Junichi MOTOHISA
Ministry of Education, Culture, Sports, Science and Technology, Competitive research funding

High-density formation of functionalized nano-interfaces based on semiconductor porous structures for high-sensitive chemical-sensing technology
Grant-in-Aid for Young Scientists (A)
2009 - 2012
SATO Taketomo
We proposed a novel ion-sensitive field-effect transistor (ISFET) having a porous-gate structure and established necessary basic technologies. The straight pores were successfully formed vertically on the substrate by the optimized electrochemical conditions. The functionalization of the pore surface was achieved by the deposition of the metal particles and organic molecules after the complete removal of the irregular top layer form the porous structures. Our proposed ISFETs with porous structures demonstrated good performance with a large current signal in the electrolyte, showing promise for high-sensitive chemical sensors.
文部科学省, 若手研究(A), 北海道大学, Principal investigator, Competitive research funding, 21686028

Reliability improvement of GaN transistors based on the control of electronic states and a nobel gate structure
Grant-in-Aid for Scientific Research (A)
2009 - 2012
Tamotsu HASHIZUME, 古賀 裕明, 久保 俊晴, 佐藤 威友, 赤澤 正道
To improve the operation stability of GaN-heterostructure transistors, we have carried out characterization and control of electronic states at insulator-semiconductor interfaces, fabrication and characterization of the multi-mesa-channel (MMC) transistors, and the related experiments. By applying the novel simulation and photo-assisted capacitance-voltage methods to Al_2O_3/ AlGaN/GaN structures, we determined the density distribution of electronic states at the Al_2O_3/AlGaN for the first time. It was also found that the MMC structure is very effective in improving the current stability of the GaN-based transistors.
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(A), 北海道大学, Coinvestigator not use grants, Competitive research funding, 21246007

化合物半導体配列ナノ構造を基盤とする超接合光吸収体の創成と太陽電池応用
Grant-in-Aid for Challenging Exploratory Research
2009 - 2010
SATO Taketomo, 橋詰 保, 本久 順一, 古賀 裕明
平成22年度は、n形インジウムリン(InP)ポーラス(多孔質)構造の内壁に白金(Pt)薄膜を形成する手法を開発し、InP配列ナノ構造を基盤とするPt/InPショットキー型光電変換素子の試作を行った。1.n形InP多孔質構造の孔内壁表面にPt薄膜を電解析出により形成する手法を開発した。真空蒸着法と比較してPt薄膜による孔内壁表面の被覆率が高く、Pt薄膜の厚さは時間により制御可能であることを明らかにした。特に電解析出電圧をパルス波形で印加することにより、膜厚の緻密な制御が可能であり、孔径600nmで深さ4μmからなる多孔質構造の内壁に厚さ20nmの均一なPt薄膜の形成に成功した。2.作製したPt/InP多孔質構造の光反射率特性を明らかにした。入射光200nm-1100nmの波長領域における光反射率は5%以下であり、平坦なInP基板と比較して表面反射が10分の1に低減されていることを明らかにした。3.作製したPt/InP多孔質構造の電気的特性を明らかにした。上部(Pt側)と下部(InP側)に電極を形成して測定した電流・電圧特性が整流性を示すことを明らかにし、Pt/InP多孔質構造の界面にショットキー障壁が形成されていることを確認した。また、光照射下では、光強度に応じて逆方向電流が増大することを明らかにした。この増加電流は、比較用に作製したPt/プレーナInP接合と比べて2～3桁大き...
Ministry of Education, Culture, Sports, Science and Technology, 挑戦的萌芽研究, 北海道大学, Principal investigator, Competitive research funding, 21656078

窒化物半導体混晶のバルク準位評価とナノ構造表面制御
Grant-in-Aid for Scientific Research on Priority Areas
2009 - 2010
Tamotsu HASHIZUME, 古賀 裕明, 佐藤 威友
AlGaNおよびAlInGaNのバルク欠陥準位と表面・端面における表面電子準位を系統的に評価し、その理解を基盤として、短波長光学素子の高効率化・動作安定化のための電子準位制御法を構築することを目的として研究を展開した。本年度の主な成果を以下にまとめる。1)減圧有機金属気相法により成長したn-AlGaN(膜厚:1μm、Al組成:25、37、60%)の深い準位を評価し、伝導帯下端より1eV以上のエネルギーを持つ電子準位を検出した。支配的準位エネルギーのAl組成依存性は、フェルミ準位安定化エネルギーの計算値に良く追従することを明らかにし、逆位置欠陥と空孔欠陥ペアの複合型欠陥が深い準位の成因である可能性を指摘した。2)原子層堆積により形成したAl_2O_3/AlGaN/GaN構造に、詳細な計算解析とバンドギャップ以下のエネルギーを持つ光支援測定法を適用し、その容量-電圧特性を評価した。その結果、Al_2O_3/AlGaN界面には1x10^<12>cm^<-2>eV^<-1>以上の密度を持つ電子準位が存在することを初めて明らかにした。3)AlGaN表面に電気化学酸化法を適用し、平坦で均一性の高い母体酸化膜を形成することができた。形成した酸化膜の組成は母体AlGaNの組成とほぼ同等であることが分かり、この手法によりAlGaNの表面準位密度を低減できることを明らかにした。また、プロセスによ...
Ministry of Education, Culture, Sports, Science and Technology, 特定領域研究, 北海道大学, Coinvestigator not use grants, Competitive research funding, 21016001

次世代センサーネットワークの実現に向けた化合物半導体化学センサの開発と高性能化に関する研究　　　　　　　　　　　　　　　
小澤・吉川記念エレクトロニクス研究助成基金
2008 - 2009
佐藤 威友
小澤・吉川記念エレクトロニクス研究助成基金, Principal investigator, Competitive research funding

Formation of three-dimensional quantum nanostructure networks based on compound semiconductor porous structuresq
Grants-in-Aid for Scientific Research(若手研究(B))
2007 - 2008
Taketomo SATO
電解液と半導体界面の電気化学反応により形成される多孔質(ポーラス)構造を利用し、少ない電子を局所的に閉じ込めて制御する「3次元量子ナノネットワーク」の基礎技術を確立した。本構造は、直径数100nm 深さ数μm の直線的な孔が配列した高密度ナノ構造が基盤となっており、非常に大きな表面積と優れた伝導特性および光学的特性を有し、高感度化学センサや高効率太陽光発電素子の基本構造として有望性を示す一連の研究成果を得た。
Ministry of Education, Culture, Sports, Science and Technology, 若手研究(B), 北海道大学, Principal investigator, Competitive research funding, 19760208

III族窒化物半導体混晶の欠陥準位・表面準位の評価と制御
科学研究費補助金(特定領域研究)
2007 - 2008
橋詰 保, 金子 昌充, 佐藤 威友
発光素子の効率・安定動作・信頼性には、バルクの結晶欠陥とともに、ヘテロ界面での禁制帯内連続電子準位(界面準位)や端面での表面準位の特性が影響する場合が多いが、これらの特性は明らかになっていない。本研究では、GaNおよびAlGaNのバルク欠陥準位と表面・端面・ヘテロ界面における表面電子準位を詳細に評価し、その特性の理解と制御を目的として研究を展開した。1) Al組成26%のAlGaN混晶にショットキー接合を形成し、暗中および光照射下での過渡容量応答評価を行なった。伝導帯下端より1.0eVおよび禁制帯中央付近の深い準位からの応答を検出し、詳しい解析の結果、5-8×10^<16>cm^<-3>程度の比較的高い密度を有することを明らかにした。2) 保護膜高温熱処理によるp-GaN表面の特性変化を詳細に評価した。XPS解析より1000℃以上の熱処理によりGa原子の外方拡散とMg原子の表面偏析が明らかになった。また、電流-電圧測定とPL評価より深い準位の生成による表面抵抗の増大が観測され、Ga空孔や格子間Mgに関連する複合欠陥の存在が示唆された。3) 電気化学酸化によるGaNおよびAlGaNの表面制御を検討した。酸化膜を溶液除去した表面に金属接合を形成した場合、接合特性の均一性が向上することが確認された。また、ドライエッチングで形成したナノ細線側面を選択的に酸化した場合、細線の伝導特性が...
文部科学省, 特定領域研究, 北海道大学, Coinvestigator not use grants, Competitive research funding, 19032001

High-efficiency energy-conversion devices based on semiconductor nanostructures　　　　　　　　　　　　　　　
2008
Competitive research funding

選択的結晶成長による窒化ガリウム系ナノワイヤ・ネットワークの作製　　　　　　　　　　　　　　　
池谷科学技術振興財団研究助成金
2006 - 2007
佐藤 威友
池谷科学技術振興財団, Principal investigator, Competitive research funding

化合物半導体ナノ構造の自己組織化形成と高感度化学センサへの応用　　　　　　　　　　　　　　　
村田学術振興財団研究助成
2006 - 2007
佐藤 威友
村田学術振興財団, Principal investigator, Competitive research funding

Reliability improvement of GaN-based devices by controlling defects and interfaces
Grants-in-Aid for Scientific Research(基盤研究(B))
2005 - 2006
Tamotsu HASHIZUME, 葛西 誠也, 佐藤 威人友, 金子 昌充
The purpose of the research is to improve the stability of the GaN-based devices by controlling defects and interfaces. We have characterized electronic states of defects and impurities in GaN and A1GaN, as well as their correlation with degradation phenomena in various kinds of devices, such as the current collapse, the gate leakage current, electric breakdown, etc.1)We performed deep level transient spectroscopy (DLTS) measurements on the Schottky contacts fabricated on the Al_0.26Ga_0.74N surfaces, and detected a deep electron trap with an activation energy of 0.9 eV and a density higher...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 北海道大学, Competitive research funding, 17360133

半導体2次元電子ガスのプラズマ波によるミリ波・テラヘルツ進行波デバイスの研究
科学研究費補助金(萌芽研究)
2005 - 2005
長谷川 英機, 葛西 誠也, 佐藤 威友, 賈 鋭
テラヘルツ(THz)帯の周波数領域では、効率よく電磁波を発生・増幅・検波する技術が確立されておらず「テラヘルツギャップ」とよばれている。本研究の目的は、ミリ波・テラヘルツ帯におい.て増幅・検波機能を果たす新しい進行波型半導体デバイスの可能性を、理論的および実験的に検討することにある。その原理は、半導体の2次元電子ガス中に発生するドリフトプラズマ波と、遅波構造による電磁波の空間高調波との相互作用を利用することにある。(1)電子の慣性項を取り入れたより厳密なプラズマ方程式をもとに、TMモード解析とグリーン関数を含むFredholm積分方程式による空間高調波解析を行い、その結果ミリ波・THz帯で、大きな負性コンダクタンスが得られことを確認した。そして、その機構が高周波では1サイクルあたりの衝突頻度が飛躍的に減ることにあることを示した。(2)さらに、解析を半導体の表面準位の効果を含むものに拡張し、表面状態による電界分布の変化やスクリーニングが、デバイスに悪影響を及ぼすことを見出した。(3)AlGaAs/GaAsヘテロ接合上に、インターディジタル型遅波構造を形成したデバイスについて、マイクロ・ミリ波帯で予備実験を行い、おおきなコンダクタンス変調を観測するとともに、理論解析と実験がよく一致することを実証した。これらは、Jpn.J.Appl.Physの正規論文やISDRS(Dec.2005...
文部科学省, 萌芽研究, 北海道大学, Coinvestigator not use grants, Competitive research funding, 17656099

ギガ・ノード超高密度量子ナノ集積構造の作製と表面制御技術の開発
科学研究費補助金(若手研究(B))
2004 - 2005
佐藤 威友
本研究の目的は、化合物半導体低損傷プロセスによる高密度量子ナノ集積構造の形成手法と、その表面および界面のナノスケール制御手法を開発し、量子集積回路実現のための基礎技術を確立することである。平成17年度の研究成果は以下のようにまとめられる。1.分子線エピタキシャル成長法(MBE)により、ガリウム砒素(GaAs)(111)B加工基板上へGaAs/AlGaAs量子細線構造の選択的成長を行い、その形成メカニズム/サイズ制御性について調べた。成長温度、材料組成を系統的に変えて行なった一連の実験結果と、吸着原子の拡散方程式に基づく成長シミュレーションの結果から、加工基板が持つ結晶面方位の違いや材料原子の種類により、表面吸着原子の拡散/取り込まれ寿命が異なり、その表面拡散論的な成長機構により、GaAs細線の断面形状が説明されることがわかった。これらの結果を基礎とし、GaAs細線の位置とサイズを数nmオーダーの精度で制御することを可能にした。また、シミュレーションにより得られた成長条件を使って、断面が1辺40nmの三角形となるGaAs細線を実験的に作製することにも成功した。2.上で開発した成長シミュレーションプログラムを、窒化ガリウム(GaN)(0001)加工基板上への選択成長に適用した。Ga原子とAl原子に対して適切な拡散係数と表面取込み寿命を設定することにより、材料組成、結晶面方位など成...
文部科学省, 若手研究(B), 北海道大学, Principal investigator, Competitive research funding, 16760239

Fabrication of Photonic Crystals by Selective-Area Metalorganic Vapor Phase Epitaxy and Their Application to Devices
Grants-in-Aid for Scientific Research(基盤研究(A))
2003 - 2005
Junichi MOTOHISA, プリミーラ モハン, 佐野 栄一, 福井 孝志, 佐藤 威友, 楊 林
We have established a method to fabricate two-dimensional crystals (2D-PhCs) and 2D-PhC slabs (2D-PhCs) by utilizing selective area metalorganic vapor phase epitaxial (SA-MOVPE) and investigated their optical properties. By doing SA-MOVPE growth on GaAs (111)B or InP(111)B substrates partially covered with periodic array of hexagonal masks, we have fabricated air-hole array of GaAs- and InP-based semiconductors. If the SA-MOVPE is carried out on sacrificial AIGaAs layer, For GaAs-based 2D-PhCs, we have succeeded in the fabrication of air-bridge-type 2D-PhCs and 2D-PhCs with line-defect and ...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(A), 北海道大学, Coinvestigator not use grants, Competitive research funding, 15206030

選択的半導体結晶成長法による量子集積回路作製プロセスの研究開発　　　　　　　　　　　　　　　
ノーステック財団基盤的研究開発育成事業（若手研究補助金）
2003 - 2004
佐藤 威友
ノーステック財団, Principal investigator, Competitive research funding

量子集積回路の実現に向けた高性能ナノショットキーゲート電極の開発
科学研究費補助金(若手研究(B))
2002 - 2003
佐藤 威友
本研究課題では、微細ゲート電極形成技術および量子集積構造作製技術といった、量子集積回路の実現に向けた量子集積プロセスの開発を目的としている。平成15年度の研究成果は、以下のようにまとめられる。1.MBE選択成長法を用いて、量子集積回路の基本構造として有望なヘキサゴナル量子ナノ細線ネットワーク構造の作製に成功した。GaAs(001)加工基板上にMBE選択成長法により、<-110>方向-<510>方向の細線からなるヘキサゴナルGaAs/AlGaAsリッジ細線ネットワークの作製に成功した。細線の位置およびサイズは、成長条件と初期加工基板の設計により精密に制御可能である。また、構造および光学的特性の評価から、1mm四方以上(ヘキサゴナルノードで約1x10^7個分の領域)の広範囲にわたり、エネルギー半値幅20meVの均一な量子閉じこめ構造が形成されていることを確認した。同様に、GaAs(111)B加工基板を用いて、三回対称性を利用したヘキサゴナル細線ネットワークを形成することにも成功した。達成したヘキサゴナルノードの密度は、約10^9cm^<-2>であり、量子デバイスの高密度化に非常に有望な結果を得た。2.MBE選択成長法により作製した量子ナノ構造をベースに、量子細線トランジスタ・二分岐スイッチングデバイスの作製に成功した(論文投稿中)。(001)GaAs加工基板上にMBE選択成長法に...
文部科学省, 若手研究(B), 北海道大学, Principal investigator, Competitive research funding, 14750223

Formation of Photonic Crystals by Selective Area Growth and Their Applications
Grants-in-Aid for Scientific Research(基盤研究(B))
2000 - 2002
Junichi MOTOHISA, 韓 哲九, 安 海岩, 藤倉 序章, 佐藤 威友, 橋詰 保
We have developed a technique to form two-dimensional periodic array of hexagonal pillars and air-hole structures for the application of two-dimensional crystals (2DPCs) by selective area metalorganic vapor phase epitaxial (SA-MOVPE) growth. Firstly, SA-MOVPE of GaAs and AlGaAs was carried out on (111)B GaAs substrates partially covered with SiO_2 masks. Array of circular or hexagonal openings of the mask pattern was arranged to realize triangular lattice with periodicity of about 0.5μm. By optimizing the growth conditions, uniform array of hexagonal pillar structures consisting of vertical...
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 北海道大学, Coinvestigator not use grants, Competitive research funding, 12450117

電気化学プロセスによる金属-化合物半導体界面の制御とその電子デバイスへの応用
科学研究費助成事業 特別研究員奨励費
1998 - 2000
佐藤 威友
日本学術振興会, 特別研究員奨励費, 北海道大学, 98J02746

Self-assembled formation of semiconductor nanostructures using electrochemcial process and its application to sensors　　　　　　　　　　　　　　　
1997
Competitive research funding

構造体の製造方法
Patent right, 堀切 文正, 福原 昇, 佐藤 威友, 渡久地 政周, 住友化学株式会社
特願2020-073936, 17 Apr. 2020
特開2020-184618, 12 Nov. 2020
特許第7597518号, 02 Dec. 2024
202403019347313470

エッチング方法及びエッチング装置
Patent right, 佐藤威友, 熊崎祐介, 橋詰保, 国立大学法人北海道大学
特願2017-095458, 12 May 2017
特開2018-195609, 06 Dec. 2018
特許第6952983号, 01 Oct. 2021
202103013888879302

構造体の製造方法
Patent right, 堀切 文正, 福原 昇, 佐藤 威友, 渡久地 政周, 株式会社サイオクス, 住友化学株式会社
特願2020-073936, 17 Apr. 2020
特開2020-184618, 12 Nov. 2020
202003005331220162

構造体の製造方法と製造装置および中間構造体
Patent right, 堀切 文正, 福原 昇, 佐藤 威友, 渡久地 政周, 株式会社サイオクス, 住友化学株式会社
特願2019-148874, 14 Aug. 2019
特開2020-184606, 12 Nov. 2020
202003010006226379

構造体の製造方法と製造装置および中間構造体
Patent right, 堀切 文正, 福原 昇, 佐藤 威友, 渡久地 政周, 株式会社サイオクス, 住友化学株式会社
特願2019-148874, 14 Aug. 2019
特許第6694102号, 20 Apr. 2020
202003007817566446

エッチング方法及びエッチング装置
Patent right, 佐藤 威友, 熊崎 祐介, 橋詰 保, 国立大学法人北海道大学
特願2017-095458, 12 May 2017
特開2018-195609, 06 Dec. 2018
201803003921498076

センサ及びセンサの製造方法
Patent right, 佐藤 威友, 国立大学法人北海道大学
特願2010-094012, 15 Apr. 2010
特開2011-226800, 10 Nov. 2011
201103012147843749

センサ及びセンサの製造方法
Patent right, 佐藤 威友, 国立大学法人北海道大学
特願2010-094012, 15 Apr. 2010
特開2011-226800, 10 Nov. 2011
特許第5339377号, 16 Aug. 2013
201403049007057533

半導体装置とその製造方法
Patent right, 杉本 雅裕, 副島 成雅, 上杉 勉, 加地 徹, 橋詰 保, 佐藤 威友, トヨタ自動車株式会社, 株式会社豊田中央研究所, 国立大学法人 北海道大学
特願2008-053543, 04 Mar. 2008
特開2009-212291, 17 Sep. 2009
200903040286249482

半導体装置とその製造方法
Patent right, 杉本 雅裕, 副島 成雅, 上杉 勉, 加地 徹, 橋詰 保, 佐藤 威友, トヨタ自動車株式会社, 株式会社豊田中央研究所, 国立大学法人 北海道大学
特願2008-053543, 04 Mar. 2008
特開2009-212291, 17 Sep. 2009
特許第5302553号, 28 Jun. 2013
201303050739924338

公開講義（札幌南高等学校）　　　　　　　　　　　　　　　
18 Oct. 2018
Lecturer
Visiting lecture
北海道大学・札幌南高等学校

公開講義（札幌開成中等教育学校）　　　　　　　　　　　　　　　
08 Aug. 2018
Lecturer, Demonstrator
Visiting lecture
北海道大学・札幌開成中等教育学校