Sugawara Hirotake
Faculty of Information Science and Technology Electronics for Informatics Integrated Systems Engineering | Associate Professor |
Education and Research Center for Mathematical and Data Science | Associate Professor |
Last Updated :2025/07/05
■Researcher basic information
Degree
Profile Information
- 主要研究テーマは放電プラズマのモデリング,電子輸送基礎理論,ならびに関連するシミュレーション技法開発。電磁界下の電子の微視的挙動からプラズマの構造や応答特性を理解することで新たな制御法や用途の開拓を目指す。
近年の課題はモンテカルロ法他を用いた磁化プラズマの解析。また,ライフワークとして,プラズマ解析の基礎となる電子エネルギー分布や電子輸送係数を電磁界や観測モードなど各種条件に合わせて算出するため,ボルツマン方程式の数値解法であるプロパゲータ法のプログラムを継続的に開発中。
語学が趣味で海外出張には現地語を学習してから臨む。
Researchmap personal page
Home Page URL
Researcher number
- 90241356
J-Global ID
Research Keyword
Research Field
Educational Organization
- Bachelor's degree program, School of Engineering
- Master's degree program, Graduate School of Information Science and Technology
- Doctoral (PhD) degree program, Graduate School of Information Science and Technology
■Career
Career
- 2004 - 2007
Hokkaido University, Graduate School of Information Science and Technology, Division of Electronics for Informatics - 2004 - 2007
Associate Professor - 2007
- 北海道大学大学院情報科学研究科情報エレクトロニクス専攻集積システム講座集積プロセス学研究室 准教授 - 2007
- Associate Professor - 1998 - 2004
北海道大学大学院工学研究科電子情報工学専攻集積材料デバイス工学講座集積電子材料工学分野 助教授 - 1998 - 2004
Associate Professor,Associate Professor, Hokkaido University - 1997 - 1998
北海道大学大学院工学研究科電子情報工学専攻集積材料デバイス工学講座集積電子材料工学分野 助手 - 1997 - 1998
Research Associate - 1995 - 1997
北海道大学工学部電子情報工学専攻集積材料デバイス工学講座集積電子材料工学分野 助手 - 1995 - 1997
Research Associate - 1992 - 1995
北海道大学工学部電気工学科電気応用工学講座 助手 - 1992 - 1995
Research Associate
Educational Background
- 1992, Hokkaido University, 工学研究科, 電気工学専攻, Japan
- 1992, Hokkaido University, Graduate School, Division of Engineering, Division of Electrical Engineering
- 1990, Hokkaido University, School of Engineering, 電気工学科, Japan
- 1990, Hokkaido University, Faculty of Engineering, Department of Electrical Engineering
Committee Memberships
- May 2018 - Present
電気学会, 編修専門第1部会委員, Society - Jan. 2018 - Present
電気学会, プラズマ・パルスパワー技術委員会1号委員, Society - Apr. 2012 - Dec. 2017
社団法人電気学会, プラズマ技術委員会1号委員, Society - Oct. 2014 - Sep. 2017
電気学会, 放電技術委員会2号委員, Society - Oct. 2014 - Sep. 2017
電気学会, 放電・プラズマ気相シミュレーション技法調査専門委員会委員長, Society - Aug. 2014 - Jul. 2016
日本学術振興会, 特別研究員等審査会専門委員, Others - Apr. 2011 - Mar. 2014
社団法人電気学会, 原子・分子衝突断面積および放電基礎データ調査専門委員会幹事, Society - 2009 - 2011
社団法人電気学会, 北海道支部協議員, Society - 2008 - 2010
社団法人電気学会, 2号代議員, Society - 2010
日本工学教育協会, 第59回工学・工業教育研究講演会実行委員, Society - 2007 - 2009
社団法人電気学会, 北海道支部総務企画幹事, Society - 2006 - 2009
社団法人電気学会, 放電技術委員会雷放電シミュレーション技術の現状とモデル間の相互比較調査専門委員会委員, Society - 2006 - 2008
社団法人電気学会, 2号代議員, Society - 2008
社団法人電気学会, 平成21年電気学会全国大会実行委員会幹事, Society - 2005 - 2007
社団法人電気学会, 放電技術委員会荷電粒子、励起種、解離種ならびに光子と原子分子ダイナミックス調査専門委員会委員, Society - 2003 - 2005
社団法人電気学会, 放電技術委員会・窒素中における放電とそのプラズマプロセスへの応用技術調査専門委員会委員, Society - 2002 - 2004
社団法人電気学会, 放電技術委員会・窒素中における放電とそのプラズマプロセスへの応用技術調査専門委員会委員, Society - 2001 - 2003
社団法人電気学会, 北海道支部会計幹事, Society - 1999 - 2000
社団法人電気学会, 平成12年電気学会基礎・材料・共通部門大会実行委員会幹事, Society - 1997
社団法人電気学会, 論文委員会委員, Society - 1994
社団法人電気学会, 平成7年電気学会全国大会実行委員会事務局, Society
■Research activity information
Awards
- Jul. 2016, 日本学術振興会, 平成27年度特別研究員等審査会専門委員(書面担当)表彰
菅原 広剛, 書面審査における有意義な審査意見, Others - 2000, 電気学会, 電気学会優秀論文発表賞
平成11年電気学会基礎・材料・共通部門大会 No. 59 (1999)菅原広剛、八幡貴志、酒井洋輔:「一定衝突周波数モデルにおける電磁界下電子群ドリフト速度のベクトル軌跡について」, Japan society, Japan - 1997, 電気学会, 電気学会優秀論文発表賞
平成8年度電気学会基礎・材料・共通部門総合研究会 ED-96-218 (1996)菅原広剛、田頭博昭、酒井洋輔:「気体中の電子群重心移動速度-速度空間モーメント方程式による導出-」, Japan society, Japan - Mar. 1995, 電気学会, 電気学会論文発表賞(賞B)
平成6年度電気関係学会北海道支部連合大会講演 No. 50 (1994)菅原広剛、酒井洋輔、田頭博昭:「気体の電離係数(CCXXXV)-完全吸収陽極近傍の電子後方拡散の効果-」, Japan society, Japan - Apr. 1992, 電気学会論文発表賞(賞A)
電気学会放電研究会講演 ED-91-69 (1991)菅原広剛、酒井洋輔、田頭博昭:「ボルツマン方程式の直接数値解法(Convective Scheme)によるArガス中電子スオームのシミュレーション」, Japan society, Japan - Aug. 1990, 電気学会, 電気学会論文発表賞(賞B)
菅原 広剛, 平成2年電気学会全国大会講演 No. 155 (1990)菅原広剛、酒井洋輔、田頭博昭:「気体の電離係数(CLXXXVIII)-ボルツマン方程式の直接数値解法-」, Japan society
Papers
- Simulation of electron energy gain in inductively coupled plasmas driven at 13.56, 27.12, and 40.68 MHz under confronting divergent magnetic fields
Ryota Okazaki, Hirotake Sugawara
Japanese Journal of Applied Physics, 63, 12, 126001, 126001, IOP Publishing, 02 Dec. 2024, [Peer-reviewed], [Last author]
English, Scientific journal, Abstract
Electron heating process in inductively coupled plasmas driven under confronting divergent magnetic fields is investigated by Monte Carlo simulations. Enhancement of the electron energy gain due to the partial resonance is demonstrated by adopting driving frequencies 27.12 and 40.68 MHz higher than the conventional 13.56 MHz. The present model reactor is arranged so that the regions of strong magnetic fields near a magnetic coil and high electric fields near the RF antenna overlap. In this configuration, with increasing driving frequency, the resonant region where the electron heating by the partial resonance occurs shifts to the region of strong magnetic and high electric fields. The enhanced electron heating observed at the higher driving frequencies indicates that the partial resonance occurs in a wider region including more electrons and under higher electric fields. The power deposition by the partial resonance exceeds the electron cooling effect of the strong magnetic fields. - Historical development of electron swarm physics based on the Boltzmann equation towards in-depth understanding of a low-temperature collisional plasma
Toshiaki Makabe, Hirotake Sugawara
Plasma Sources Science and Technology, 33, 9, 093001, 093001, IOP Publishing, 01 Sep. 2024, [Peer-reviewed], [Invited]
English, Scientific journal, Abstract
Theoretical study of the electron kinetics (i.e. the velocity distribution and the transport parameter) in gases is generally conducted using the electron Boltzmann equation. The year 2022 marked 150 years since the formulation of the Boltzmann equation. Even in the last several decades, the historical progress has been made synchronously with the development of innovative technologies in gaseous electronics and in combination with the appearance of computers with sufficient speed and memory. Electron kinetic theory based on the Boltzmann equation has mostly been developed as the swarm physics in the hydrodynamic regime in the dc and radio frequency electric fields. In particular, the temporal characteristics are understood in terms of the collisional relaxation times between electron and gas molecule. There are two main theoretical approaches based on the Boltzmann equation for finding the velocity distribution. One is the traditional description of the electron kinetics, starting from the Boltzmann statistics in velocity space under a uniform density or a small density gradient of electrons. The other most recent approach is based on the phase-space tracking of the velocity distribution where the electron transport parameter is given by the moment of the electron density distribution in position space. In the present paper, we will explore the historical development of the electron Boltzmann equation with respect to three key items: collision term, solution method, and intrinsic electron transport in a hydrodynamic regime involved as the key elements in the low-temperature collisional plasma. The important topics listed in a table are briefly noted and discussed. - Particle Propagation and Electron Transport in Gases
Luca Vialetto, Hirotake Sugawara, Savino Longo
Plasma, 7, 1, 121, 145, MDPI AG, 16 Feb. 2024, [Peer-reviewed]
English, Scientific journal, In this review, we detail the commonality of mathematical intuitions that underlie three numerical methods used for the quantitative description of electron swarms propagating in a gas under the effect of externally applied electric and/or magnetic fields. These methods can be linked to the integral transport equation, following a common thread much better known in the theory of neutron transport than in the theory of electron transport. First, we discuss the exact solution of the electron transport problem using Monte Carlo (MC) simulations. In reality we will go even further, showing the interpretative role that the diagrams used in quantum theory and quantum field theory can play in the development of MC. Then, we present two methods, the Monte Carlo Flux and the Propagator method, which have been developed at this moment. The first one is based on a modified MC method, while the second shows the advantage of explicitly applying the mathematical idea of propagator to the transport problem. - An improved calculation scheme of electron flow in propagator method for solving the Boltzmann equation
Tsukasa Kobayashi, Hirotake Sugawara, Kei Ikeda
Japanese Journal of Applied Physics, 62, SL, SL1020-1, SL1020-10, IOP Publishing, 11 May 2023, [Peer-reviewed]
Scientific journal, Abstract
In order to accurately evaluate the electron acceleration process in the time evolution calculation of electron velocity distribution function (EVDF) based on the Boltzmann equation, an improved scheme blending upwind and central differences is introduced into the propagator method (PM). While the previous PM based on the upwind scheme needs fine cells to obtain an accurate EVDF at low electric fields, the improved PM is robust against coarse cells, which allows the reduction of the cell resolution. Calculations of the EVDF in Ar under RF electric fields demonstrated that the blending scheme can provide satisfactorily accurate results even with cells about tenfold larger than the upwind case at low reduced electric fields below 1 Td, which leads to much shorter computational time because the reduction of number of cells satisfactorily compensates the complexity of the blending scheme. This technique has been built into a new user-friendly PM software named BOSPROM. - Analysis of electron heating due to partial resonance in an inductively coupled plasma under confronting divergent magnetic fields
Ryota Okazaki, Hirotake Sugawara
Japanese Journal of Applied Physics, 62, SL, SL1003-1, SL1003-8, IOP Publishing, 12 Apr. 2023, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal, Abstract
We investigate the partial resonance as one of the mechanisms of the electron heating to sustain inductively coupled plasmas driven under confronting divergent magnetic fields having an electron confinement function. Dependence of the partial resonance on operating conditions are observed. The electron energy gain (EEG), defined as a measure for evaluation of the partial resonance, was calculated by a Monte Carlo method under various magnetic field strengths and the RF antenna positions. It is confirmed that the partial resonance is observed in the resonant region even in low electric field and strong magnetic field. As an attempt to utilize the partial resonance, we demonstrate enhancement of the EEG and resulting ionization in the resonant region by placing the RF antenna near a region where the magnetic field lines running through the resonant region reach. 
, 13888736 - Effects of a small amount of H2O on negative ion mobility and ion‐molecule reactions in O2 at atmospheric pressure
Yui Okuyama, Yuka Yasuzawa, Hirotake Sugawara
Electrical Engineering in Japan, 216, 1, Wiley, 07 Feb. 2023, [Peer-reviewed], [Last author]
English, Scientific journal - Effects of a Small Amount of H2O on Negative Ion Mobility and Ion-Molecule Reactions in O2 at Atmospheric Pressure
Yui Okuyama, Yuka Yasuzawa, Hirotake Sugawara
IEEJ Transactions on Fundamentals and Materials, 142, 10, 397, 405, Institute of Electrical Engineers of Japan (IEE Japan), 01 Oct. 2022, [Peer-reviewed], [Last author]
Japanese, Scientific journal - A Measure for the Electron Energy Gain by Partial Resonance around the Resonant Magnetic Field Region in an Inductively Coupled Magnetized Plasma
Naoto Nohara, Hirotake Sugawara
IEEJ Transactions on Fundamentals and Materials, 142, 6, 288, 289, Institute of Electrical Engineers of Japan (IEE Japan), 01 Jun. 2022, [Peer-reviewed], [Last author, Corresponding author]
Japanese, Scientific journal, 13888736 - Elliptic vector loci of average electron velocity of electron swarm in constant-collision-frequency model gas under ac electric and dc magnetic fields crossed at arbitrary angles
Hirotake Sugawara, Yuya Nakata
The European Physical Journal D, 76, 2, 32-1, 32-11, Springer Science and Business Media LLC, Feb. 2022, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal, 13888736 - A technology demonstration of propagator matrix power method for calculation of electron velocity distribution functions in gas in long-term transient and succeeding equilibrium states under dc electric fields
Hirotake Sugawara, Hikaru Iwamoto
Japanese Journal of Applied Physics, 60, 4, 046001, 046001, IOP Publishing, 01 Apr. 2021, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal - Stochastic electron energy gain under sheath electric field near sidewall of chamber to drive inductively coupled magnetized plasmas
H. Takahashi, H. Sugawara
Japanese Journal of Applied Physics, 59, 3, 036001-1, 036001-6, 17 Feb. 2020, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal, 11497835 - Elliptic Vector Loci of Average Electron Velocity in Real Gases Under AC Electric and DC Magnetic Fields
Yuya Nakata, Takeshi Sato, Hirotake Sugawara
IEEE Transactions on Plasma Science, 49, 1, 83, 90, Institute of Electrical and Electronics Engineers (IEEE), 2020, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal, 13888736 - Phase-resolved profile of electron energy deposition in inductively coupled radio-frequency plasmas driven under confronting divergent magnetic fields
NAKASHIMA Katsuhiro, TAKAHASHI Hironori, SUGAWARA Hirotake
Japanese Journal of Applied Physics, 58, 11, 116001-1, 116001-7, Nov. 2019, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal - Derivation of the electron drift velocity vector in gas under crossed ac electric and dc magnetic fields assuming constant-collision-frequency models
Hirotake SUGAWARA
Japanese Journal of Applied Physics, 58, 10, 108002-1, 108002-4, Oct. 2019, [Peer-reviewed], [Lead author, Last author, Corresponding author]
English, Scientific journal - Quantification of electron confinement effect of confronting divergent magnetic fields applied to an inductively coupled plasma and its dependence on control parameters
OZAWA Ryosuke, SUGAWARA Hirotake
IEEJ Transactions A, 139, 5, 283, 284, May 2019, [Peer-reviewed], [Last author, Corresponding author]
Japanese, Scientific journal - Configuration of propagator method for calculation of electron velocity distribution function in gas under electric and magnetic fields crossed at a right angle
SUGAWARA Hirotake
Plasma Science and Technology, 21, 9, 094001-1, 094001-18, 2019, [Peer-reviewed], [Lead author, Last author, Corresponding author]
English, Scientific journal - Stochastic electron energy gain accompanying electron reflection at chamber wall in inductively coupled magnetized plasmas
H. Takahashi, K. Nakashima, T. Yamamoto, H. Sugawara
Japanese Journal of Applied Physics, 57, 12, 126101-1, 126101-7, Dec. 2018, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal - Efficiency and limitation of periodic sample multiplication to reduce computational load in Monte Carlo simulations of electron swarms in gas under attachment-dominated conditions
Hirotake Sugawara
Japanese Journal of Applied Physics, 57, 3, 038001-1, 038001-3, Japan Society of Applied Physics, 01 Mar. 2018, [Peer-reviewed], [Lead author, Last author, Corresponding author]
English, Scientific journal - A computational scheme of propagator method for moment equations to derive real-space electron transport coefficients in gas under crossed electric and magnetic fields
SUGAWARA Hirotake
IEEE Transactions on Plasma Science, 47, 2, 1071, 1082, Feb. 2018, [Peer-reviewed], [Lead author, Last author, Corresponding author]
English, Scientific journal - A relaxation-accelerated propagator method for calculations of electron energy distribution function and electron transport parameters in gas under dc electric fields
Hirotake Sugawara
PLASMA SOURCES SCIENCE & TECHNOLOGY, 26, 4, 044002-1, 044002-16, Apr. 2017, [Peer-reviewed], [Lead author, Last author, Corresponding author]
English, Scientific journal - On judgement of electron escape for evaluation of the magnetic confinement effect in simulations of inductively coupled plasmas under confronting divergent magnetic fields
Tappei Yamamoto, Hirotake Sugawara
IEEJ Transactions on Fundamentals and Materials, 137, 6, 363, 364, Institute of Electrical Engineers of Japan, 2017, [Peer-reviewed], [Last author, Corresponding author]
Japanese, Scientific journal - Fundamental study on filter effect of confronting divergent magnetic fields applied to low-pressure inductively coupled plasmas
Hirotake Sugawara, So Ogino
JAPANESE JOURNAL OF APPLIED PHYSICS, 55, 7, 07LD05-1, 07LD05-6, Jul. 2016, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal - Structure and Energy Deposition Process of an Inductively Coupled Plasma Under Confronting Divergent Magnetic Fields
Yudai Minami, Yusuke Asami, Hirotake Sugawara
IEEE TRANSACTIONS ON PLASMA SCIENCE, 42, 10, 2550, 2551, Oct. 2014, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal - Effect of Substrate Bias on Production and Transport of Etchant Ions in a Magnetic Neutral Loop Discharge Plasma
Yusuke Asami, Hirotake Sugawara
IEEE TRANSACTIONS ON PLASMA SCIENCE, 42, 10, 2540, 2541, Oct. 2014, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal - Control of Magnetic Field for Sustainment of Ion Production and Uniform Ion Flux to Substrate in Neutral Loop Discharge Plasma
Takuhei Yoshida, Yohei Sakurai, Hirotake Sugawara, Akihiro Murayama
ELECTRICAL ENGINEERING IN JAPAN, 185, 1, 9, 16, Oct. 2013, [Peer-reviewed], [Corresponding author]
English, Scientific journal - Scattering-Based Stochastic Process Attracting Electrons Inward under Antiparallel Gradient Magnetic Fields
Hirotake Sugawara
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 82, 6, 064501-1, 064501-6, Jun. 2013, [Peer-reviewed], [Lead author, Last author, Corresponding author]
English, Scientific journal - Characteristics of Electron Conduction in a Gas under a Quadrupole Magnetic Field and Radio-Frequency Electric Fields
Hirotake Sugawara
JAPANESE JOURNAL OF APPLIED PHYSICS, 52, 5, 056101-1, 056101-5, May 2013, [Peer-reviewed], [Lead author, Last author, Corresponding author]
English, Scientific journal - Control of magnetic field for sustainment of ion production and uniform ion flux to substrate in neutral loop discharge plasma
Takuhei Yoshida, Yohei Sakurai, Hirotake Sugawara, Akihiro Murayama
IEEJ Transactions on Fundamentals and Materials, 132, 4, 278, 283, 2012, [Peer-reviewed], [Corresponding author]
Japanese, Scientific journal - Structure and dynamics of a magnetic neutral loop discharge plasma described using electron motion in a quadrupole magnetic field
Tsuyoshi Osaga, Hirotake Sugawara, Yohei Sakurai
PLASMA SOURCES SCIENCE & TECHNOLOGY, 20, 6, 065003-1, 065003-7, Dec. 2011, [Peer-reviewed], [Corresponding author]
English, Scientific journal - Remote Plasma Chemical Vapor Deposition of Carbon Nanotubes and Analysis of Plasma Effect
Yushi Fukuda, Junichi Takayama, Norichika Asaoka, Yoshiyuki Suda, Hirotake Sugawara, Akihiro Murayama
IEEE TRANSACTIONS ON PLASMA SCIENCE, 39, 11, 3133, 3139, Nov. 2011, [Peer-reviewed]
English, Scientific journal - Electron Distribution in a Quadrupole Magnetic Field to Drive Magnetic Neutral Loop Discharge Plasma
Tsuyoshi Osaga, Yohei Sakurai, Hirotake Sugawara
IEEE TRANSACTIONS ON PLASMA SCIENCE, 39, 11, 2546, 2547, Nov. 2011, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal - Control of Magnetic Field in Neutral Loop Discharge Plasma for Uniform Distribution of Ion Flux on Substrate
Yohei Sakurai, Tsuyoshi Osaga, Hirotake Sugawara
IEEE TRANSACTIONS ON PLASMA SCIENCE, 39, 11, 2550, 2551, Nov. 2011, [Peer-reviewed]
English, Scientific journal - Rectification effect of gradient antiparallel magnetic fields on electron conduction in a gas under a radio-frequency electric field
Hirotake Sugawara, Tsuyoshi Osaga, Hiromori Yamamoto
PLASMA SOURCES SCIENCE & TECHNOLOGY, 20, 5, 055002-1, 055002-7, Oct. 2011, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal - Numerical Simulation of Electron Transport in Electric and Magnetic Fields for Analysis of Electron Temperature and Number Density Profiles Measured in Argon Magnetic Neutral Loop Discharge Plasma
Hirotake Sugawara, Tsuyoshi Osaga, Hideo Tsuboi, Kiyoshi Kuwahara, Seiji Ogata
JAPANESE JOURNAL OF APPLIED PHYSICS, 49, 8, 086001-1, 086001-5, Aug. 2010, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal - Deposition of Wave-shaped Layered Low-k Dielectric a-C:F Films by C8F18 Plasma CVD
Kouichiro Mizuno, Hirotake Sugawara, Akihiro Murayama
IEEJ Transactions on Fundamentals and Materials, 130, 4, 319, 324, 2010, [Peer-reviewed]
English, Scientific journal - Carbon-Nanotube Growth in Alcohol-Vapor Plasma
Yoshiyuki Suda, Atsushi Okita, Junichi Takayama, Akinori Oda, Hirotake Sugawara, Yosuke Sakai, Shinichiro Oke, Hirofumi Takikawa
IEEE TRANSACTIONS ON PLASMA SCIENCE, 37, 7, 1150, 1155, Jul. 2009, [Peer-reviewed]
English, Scientific journal - Is the Diameter or Chirality Distribution of Single-Walled Carbon Nanotubes Selected in the Synthesis Process?
Krishnendu Bhattacharyya, Yoshiyuki Suda, Atsushi Okita, Takeshi Saito, Atsushi Ozeki, Masayuki Maekawa, Junichi Takayama, Hirotake Sugawara, Yosuke Sakai
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY, 9, 3, 1897, 1903, Mar. 2009, [Peer-reviewed]
English, Scientific journal - Electron transport in carbon tetrafluoride along a magnetically neutral plane between constant gradient antiparallel magnetic fields
Hirotake Sugawara, Yosuke Sakai
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 41, 13, 135208-1, 135208-7, Jul. 2008, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal - Evaluation of ion and radical fluxes in CH4/H2 plasma for CNT growth
Youhei Hizume, Atsushi Okita, Akinori Oda, Hirotake Sugawara, Yoshiyuki Suda, Yosuke Sakai
IEEJ Transactions on Fundamentals and Materials, 128, 10, 5, 628, 2008, [Peer-reviewed]
English, International conference proceedings - Dual distributions for the metallic and semiconducting single-walled carbon nanotubes observed by Raman spectroscopy
K. Bhattacharyya, Y. Suda, A. Okita, T. Saito, A. Ozeki, M. Maekawa, J. Takayama, H. Sugawara, Y. Sakai
Carbon - Sci. Tech., 1, 4, 8, 2008, [Peer-reviewed]
English, Scientific journal - Effects of hydrogen on carbon nanotube formation in CH4/H-2 plasmas
Atsushi Okita, Yoshiyuki Suda, Akinori Oda, Junji Nakamura, Atsushi Ozeki, Krishnendu Bhattacharyya, Hirotake Sugawara, Yosuke Sakai
CARBON, 45, 7, 1518, 1526, Jun. 2007, [Peer-reviewed]
English, Scientific journal - Timesaving techniques for decision of electron-molecule collisions in Monte Carlo simulation of electrical discharges
Hirotake Sugawara, Naoki Mori, Yosuke Sakai, Yoshiyuki Suda
JOURNAL OF COMPUTATIONAL PHYSICS, 223, 1, 298, 304, Apr. 2007, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal - Hydrogen-sensing response of carbon-nanotube thin-film sensor with Pd comb-like electrodes
Yuki Hayakawa, Yoshiyuki Suda, Tamotsu Hashizume, Hirotake Sugawara, Yosuke Sakai
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS, 46, 12-16, L362, L364, Apr. 2007, [Peer-reviewed]
English, Scientific journal - Analysis of oxidation state of multilayered catalyst thin films for carbon nanotube growth using plasma-enhanced chemical vapor deposition
Atsushi Okita, Atsushi Ozeki, Yoshiyuki Suda, Junji Nakamura, Akinori Oda, Krishnendu Bhattacharyya, Hirotake Sugawara, Yosuke Sakai
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, 45, 10B, 8323, 8329, Oct. 2006, [Peer-reviewed]
English, Scientific journal - Equality of higher-order diffusion coefficients between component and composite electron swarms in gas
H Sugawara, Y Sakai
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, 45, 6A, 5189, 5196, Jun. 2006, [Peer-reviewed]
English, Scientific journal - Correlation between a-C : H film properties and Ar/CH4 dielectric barrier discharge
MA Bratescu, Y Yoshizaki, Y Suda, Y Sakai, H Sugawara, O Takai
THIN SOLID FILMS, 506, 145, 149, May 2006, [Peer-reviewed]
English, Scientific journal - Predicting the amount of carbon in carbon nanotubes grown by CH4 rf plasmas
A Okita, Y Suda, A Ozeki, H Sugawara, Y Sakai, A Oda, J Nakamura
JOURNAL OF APPLIED PHYSICS, 99, 1, 014302-1, 014302-7, Jan. 2006, [Peer-reviewed]
English, Scientific journal - Analysis of CH4 rf plasmas for carbon naotube growth: Comparison between computer modeling and experimental results
A.Okita, Y.Suda, A.Ozeki, H.Sugawara, Y.Sakai, A.Oda, J.Nakamura, 中村, 潤児
J.Appl.Phys, 99, 014302, Jan. 2006, [Peer-reviewed]
English, Scientific journal - Two-peaked velocity distribution function of electrons in carbon tetrafluoride in crossed electric and magnetic fields
H Sugawara, A Oda, Y Sakai
IEEE TRANSACTIONS ON PLASMA SCIENCE, 33, 2, 548, 549, Apr. 2005, [Peer-reviewed]
English, Scientific journal - Investigation of excited species in a carbon ablation plume in nitrogen gas environment
M. A. Bratescu, Y. Sakai, N. Sakura, D. Yamaoka, Y. Suda, H. Sugawara
Plasma Processes and Polymers, 489, 498, 2005, [Peer-reviewed]
English, Scientific journal - Analysis of plasma for carbon nanotube growth by plasma-enhanced chemical vapor deposition
A. Ozeki, Y. Suda, A. Okita, J. Nakamura, A. Oda, Y. Sakai, H. Sugawara
Materials Research Society Symposium Proceedings, 901, 523, 528, Materials Research Society, 2005
English, International conference proceedings - Effect of near-threshold ionization on electron attachment in gaseous dielectrics
H Sugawara, T Ishigaki, Y Hirochi, Y Sakai
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 43, 11A, 7705, 7706, Nov. 2004, [Peer-reviewed]
English, Scientific journal - Spectroscopic measurements of excited particles in a N-2 gas RF plasma-assisted carbon laser ablation
MA Bratescu, N Sakura, D Yamaoka, Y Sakai, H Sugawara, Y Suda
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 79, 4-6, 1083, 1088, Sep. 2004, [Peer-reviewed]
English, Scientific journal - Amorphous fluorocarbon polymer (a-C : F) films obtained by plasma enhanced chemical vapor deposition from perfluoro-octane (C8F18) vapor. II. Dielectric and insulating properties
C Biloiu, IA Biloiu, Y Sakai, H Sugawara, A Ohta
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A, 22, 4, 1158, 1165, Jul. 2004, [Peer-reviewed]
English, Scientific journal - Electron-Molecule Collisional Processes in Insulating Gas Mixtures —Investigation of Synergy Mechanism—
Takuya Ishigaki, Yuuki Hirochi, Hirotake Sugawara, Yosuke Sakai
IEEJ Transactions on Fundamentals and Materials, 124, 2, 126, 131, 2004, [Peer-reviewed]
English, Scientific journal - Laser Spectroscopy of the Ar(1s3,5) and CH in Ar + CH4 DBD for a-C:H Deposition System
Yasunao Yoshizaki, Maria-Antoaneta Bratescu, Yosuke Sakai, Yoshiyuki Suda, Hirotake Sugawara
IEEJ Transactions on Fundamentals and Materials, 124, 2, 158, 163, 2004, [Peer-reviewed]
English, Scientific journal - Electron acceleration in gas by impulse electric field and its application to selective promotion of an electron-molecule reaction
H Sugawara, Y Sakai
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 36, 16, 1994, 2000, Aug. 2003, [Peer-reviewed]
English, Scientific journal - Two-dimensional modelling of CF4 rf plasmas: periodic steady state, transient response after step change of power source voltage, and comparison with one-dimensional modelling
SY So, A Oda, H Sugawara, Y Sakai
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 35, 22, 2978, 2987, Nov. 2002, [Peer-reviewed]
English, Scientific journal - Electron and excited particle densities in a carbon ablation plume
MA Bratescu, Y Sakai, D Yamaoka, Y Suda, H Sugawara
APPLIED SURFACE SCIENCE, 197, 257, 262, Sep. 2002, [Peer-reviewed]
English, Scientific journal - プラズマディスプレイ用混合希ガス中の励起移行効果
内田諭, 菅原広剛, 酒井洋輔, 渡辺恒雄
電気学会論文誌A, 122-A, 8, 729, 735, 2002, [Peer-reviewed]
Japanese, Scientific journal - Barrier effect of collisional processes on electron swarms in nitrogen
H Sugawara, K Satoh, Y Sakai
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 34, 21, 3191, 3196, Nov. 2001, [Peer-reviewed]
English, Scientific journal - Transient behaviour of CF4 rf plasmas after step changes of power source voltage
SY So, A Oda, H Sugawara, Y Sakai
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 34, 12, 1919, 1927, Jun. 2001, [Peer-reviewed]
English, Scientific journal - Addition of Ar to Xe/Ne and Xe/He mixtures: radiation characteristics and discharge onset voltage for an application of plasma display technology
S Uchida, H Sugawara, Y Sakai, T Watanabe, BH Hong
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 34, 6, 947, 953, Mar. 2001
English, Scientific journal - CxFy polymer film deposition in rf and dc C7F16 vapor plasmas
Y. Sakai, M. Akazawa, Y. Sakai, H. Sugawara, M. Tabata, C. P. Lungu, A. M. Lungu
Transactions of Korean Institute of Electrical and Electronic Material Engineers, 2, 1, 1, 6, Mar. 2001, [Peer-reviewed]
English, Scientific journal - CxFy polymer film deposition in DC and RF fluorinert vapor plasmas
CP Lungu, AM Lungu, Y Sakai, H Sugawara, M Tabata, M Akazawa, M Miyamoto
VACUUM, 59, 1, 210, 219, Oct. 2000, [Peer-reviewed]
English, Scientific journal - Estimation of the light output power and efficiency of Xe barrier discharge excimer lamps using a one-dimensional fluid model for various voltage waveforms
A Oda, H Sugawara, Y Sakai, H Akashi
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 33, 12, 1507, 1513, Jun. 2000, [Peer-reviewed]
English, Scientific journal - The drift velocity vector of electron swarms in crossed electric and magnetic fields
H Sugawara, T Yahata, A Oda, Y Sakai
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 33, 10, 1191, 1196, May 2000, [Peer-reviewed]
English, Scientific journal - Two-dimensional fluid simulation of plasma reactors for the immobilization of krypton
E Suetomi, M Tanaka, S Kamiya, S Hayashi, S Ikeda, H Sugawara, Y Sakai
COMPUTER PHYSICS COMMUNICATIONS, 125, 1-3, 60, 74, Mar. 2000, [Peer-reviewed]
English, Scientific journal - Boltzmann equation analysis of electron swarm parameters and related properties of Xe/He and Xe/Ne mixtures used for plasma display panels
S Uchida, H Sugawara, Y Sakai, T Watanabe, BH Hong
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 33, 1, 62, 71, Jan. 2000, [Peer-reviewed]
English, Scientific journal - Fluorinated carbon films with low dielectric constant made from novel fluorocarbon source materials by RF plasma enhanced chemical vapor deposition
CP Lungu, AM Lungu, M Akazawa, Y Sakai, H Sugawara, M Tabata
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS, 38, 12B, L1544, L1546, Dec. 1999, [Peer-reviewed]
English, Scientific journal - One-dimensional modelling of low-frequency and high-pressure Xe barrier discharges for the design of excimer lamps
A Oda, Y Sakai, H Akashi, H Sugawara
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 32, 21, 2726, 2736, Nov. 1999, [Peer-reviewed]
English, Scientific journal - An analysis of transverse evolution of electron swarms in gases using moment equations and a propagator method
H Sugawara, Y Sakai
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 32, 14, 1671, 1680, Jul. 1999, [Peer-reviewed]
English, Scientific journal - The 1997 Convertion of Fundamentals and Materials Saciety of IEE of Japan. A Boltzmann Equation Analysis of Electron Swarm Parameters and Properties of Excited Particle Number Densities in Xe/Ne Plasmas. Laser Absorption Effect.
内田論, 菅原広剛, VENTZEK P L G, 酒井洋輔
電気学会論文誌 A, 118-A, 6, 622, 628, Jun. 1998, [Peer-reviewed]
Japanese, Scientific journal - The spatio-temporal development of electron swarms in gases: moment equation analysis and Hermite polynomial expansion
H Sugawara, Y Sakai, H Tagashira, K Kitamori
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 31, 3, 319, 327, Feb. 1998, [Peer-reviewed]
English, Scientific journal - Step responses of radio-frequency capacitively coupled discharges
J Yang, PLG Ventzek, H Sugawara, Y Sakai, K Kitamori, H Tagashira
JOURNAL OF APPLIED PHYSICS, 82, 5, 2093, 2105, Sep. 1997, [Peer-reviewed]
English, Scientific journal - Centroid drift velocity of electron swarms in gases
H. Sugawara, H. Tagashira, Y. Sakai
電気学会論文誌A, 117-A, 7, 749, 753, Jun. 1997, [Peer-reviewed]
Japanese, Scientific journal - Evaluation of the real space electron drift velocity in gases using moment equations performed in velocity space
H Sugawara, H Tagashira, Y Sakai
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 30, 3, 368, 373, Feb. 1997, [Peer-reviewed]
English, Scientific journal - The velocity distribution of ions in warm gas under a constant-collision-frequency symmetric charge exchange model
H Sugawara, H Tagashira, Y Sakai
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 29, 5, 1168, 1174, May 1996, [Peer-reviewed]
English, Scientific journal - PROPERTIES OF ELECTRON SWARMS IN GASES IN THE UPSTREAM REGION OF AN ELECTRON SOURCE
H SUGAWARA, Y SAKAI, H TAGASHIRA
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 28, 1, 61, 67, Jan. 1995, [Peer-reviewed]
English, Scientific journal - ANALYSES OF ELECTRON SWARMS IN GASES UNDER STEADY-STATE TOWNSEND CONDITIONS
H SUGAWARA, Y SAKAI, H TAGASHIRA
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 27, 1, 90, 94, Jan. 1994, [Peer-reviewed]
English, Scientific journal - POSITION-DEPENDENT ELECTRON SWARM BEHAVIOR IN STEADY-STATE TOWNSEND DISCHARGES
H SUGAWARA, Y SAKAI, H TAGASHIRA
JOURNAL OF PHYSICS D-APPLIED PHYSICS, 25, 10, 1483, 1487, Oct. 1992, [Peer-reviewed]
English, Scientific journal
Other Activities and Achievements
- Role of aluminum oxide support layer in growth of carbon nanotubes by plasma-enhanced chemical vapor deposition
Y. Suda, A. Ozeki, A. Okita, J. Nakamura, A. Oda, Y. Sakai, H. Sugawara, S. Oke, H. Takikawa, Industrial Application of Plasma Process, 3, 41, 52, Nov. 2010, [Peer-reviewed] - Carbon nanotube growth by alcohol plasma-enhanced chemical vapor deposition
OKITA Atsushi, SUDA Yoshiyuki, SUGAWARA Hirotake, SAKAI Yosuke, ODA Akinori, NAKAMURA Junji, 電気学会研究会資料. ED, 放電研究会, 2008, 37, 43, 47, 10 Mar. 2008
Japanese - Monte Carlo analysis of the pressure-dependence of periodical response of the electron energy distribution in radio-frequency CF_4 plasma
MORI Naoki, SUGAWARA Hirotake, ARAKITA Daishi, EGUCHI Noriyoshi, SUDA Yoshiyuki, SAKAI Yosuke, 電気学会研究会資料. ED, 放電研究会, 2008, 37, 7, 12, 10 Mar. 2008
Japanese - Monte Carlo simulation of promotion of CF_4 dissociation reaction by impulse-field electron acceleration method under low pressures
ARAKITA Daishi, EGUCHI Noriyoshi, MORI Naoki, SUGAWARA Hirotake, SAKAI Yosuke, SUDA Yoshiyuki, 電気学会研究会資料. ED, 放電研究会, 2008, 37, 1, 5, 10 Mar. 2008
Japanese - Growth Promotion and Etching of Carbon Nanotubes by Carbon Dioxide in Chemical Vapor Deposition using Methane Gas
Yoshiyuki Suda, Junichi Takayama, Takeshi Saito, Atsushi Okita, Junji Nakamura, Yosuke Sakai, Hirotake Sugawara, Materials Research Society Symposium Proceedings, 1057-II05-15 (6 pages), 2008, [Peer-reviewed] - Plasma-enhanced chemical vapor deposition of carbon nanotubes using alcohol vapor
Atsushi Okita, Yoshiyuki Suda, Masayuki Maekawa, Junichi Takayama, Akinori Oda, Hirotake Sugawara, Yosuke Sakai, Materials Research Society Symposium Proceedings, 1057-II05-10 (7 pages), 2008, [Peer-reviewed] - Growth of Carbon Nanotubes by Hydrocarbon Plasma and its Plasma Analysis : Influence of Gas Flow Ratio on Carbon Nanotube Growth
SUDA Yoshiyuki, OKITA Atsushi, ODA Akinori, NAKAMURA Junji, SUGAWARA Hirotake, SAKAIA Yosuke, 電気学会研究会資料. PST, プラズマ研究会, 2007, 80, 13, 17, 22 Dec. 2007
Japanese - ICPIG-28(電離気体中の現象に関する国際会議)
菅原 広剛, 電気学会論文誌. A, 基礎・材料・共通部門誌 = The transactions of the Institute of Electrical Engineers of Japan. A, A publication of Fundamentals and Materials Society, 127, 12, 785, 785, 01 Dec. 2007
Japanese - a-C:F Films Deposition by C_8F_<18> Plasma CVD and Measurement of Their Properties
KOIKE Hiroe, SUGAWARA Hirotake, SAKAI Yosuke, SUDA Yoshiyuki, YAMAUCHI Tatsuya, 電気学会研究会資料. PST, プラズマ研究会, 2007, 42, 65, 70, 13 Sep. 2007
Japanese - Analysis of electron energy distribution in radio-frequency CF_4 plasma using Monte Carlo method
MORI Naoki, SUGAWARA Hirotake, ARAKITA Daishi, EGUCHI Noriyosi, SUDA Yoshiyuki, SAKAI Yosuke, 電気学会研究会資料. PST, プラズマ研究会, 2007, 42, 37, 42, 13 Sep. 2007
Japanese - Dependence of Co/Mo catalyst condition on CNTs growth by alcohol chemical vapor deposition
MAEKAWA Masayuki, SUDA Yoshiyuki, OKITA Atsushi, SUGAWARA Hirotake, SAKAI Yosuke, 電気学会研究会資料. PST, プラズマ研究会, 2007, 42, 53, 57, 13 Sep. 2007
Japanese - Efficiency of CF_4 molecule and CF_x radical decomposition by impulse-field electron acceleration
ARAKITA Daishi, EGUCHI Noriyoshi, MORI Naoki, SUGAWARA Hirotake, SAKAI Yosuke, SUDA Yoshiyuki, 電気学会研究会資料. PST, プラズマ研究会, 2007, 42, 33, 36, 13 Sep. 2007
Japanese - Growth of carbon nanofibers on metal-catalyzed substrates by pulsed laser ablation of graphite
Y. Suda, A. Tanaka, A. Okita, Y. Sakai, H. Sugawara, COLA'05: 8TH INTERNATIONAL CONFERENCE ON LASER ABLATION, 59, 348, +, 2007, [Peer-reviewed]
English - Electron-Molecule Collisional Processes in Insulating Gas Mixtures —Investigation of Synergy Mechanism—
Takuya Ishigaki, Yuuki Hirochi, Hirotake Sugawara, Yosuke Sakai, IEEJ Transactions on Fundamentals and Materials, 124, 2, 126, 131, 2004
English - Laser Spectroscopy of the Ar(1s3,5) and CH in Ar + CH4 DBD for a-C:H Deposition System
Yasunao Yoshizaki, Maria-Antoaneta Bratescu, Yosuke Sakai, Yoshiyuki Suda, Hirotake Sugawara, IEEJ Transactions on Fundamentals and Materials, 124, 2, 158, 163, 2004
English - Generation of carbon nanotube by short-wavelength laser ablation
UTAKA K., SUDA Y., BRATESCU M. A., SAKAI Y., SUGAWARA H., 電気学会研究会資料. ED, 放電研究会, 2003, 107, 43, 48, 05 Aug. 2003
Japanese - Evaluation of carbon thin films deposited by oxygen plasma assisted PLD method
ONO Tomoyuki, SUDA Yoshiyuki, AKAZAWA Masamichi, SUGAWARA Hirotake, SAKAI Yosuke, SUZUKI Kaoru, 電気学会基礎・材料・共通部門大会講演論文集 = Proceeding of Annual Conference of Fundamentals and Materials Society, IEE Japan, 2001, 381, 386, 21 Sep. 2001
Japanese - Deposition of B and/or N doped amorphous carbon films by Plasma assisted PLD method
ONO Tomoyuki, SUGANUMA Yuya, SUDA Yoshiyuki, SUGAWARA Hirotake, SAKAI Yosuke, 電気学会基礎・材料・共通部門大会講演論文集 = Proceeding of Annual Conference of Fundamentals and Materials Society, IEE Japan, 2001, 28, 28, 21 Sep. 2001
Japanese - Effect of Excitation Transfer in Rare Gas Mixtures for Plasma Display Panels
UCHIDA Satoshi, SUGAWARA Hirotake, SAKAI Yosuke, WATANABE Tsuneo, 電気学会基礎・材料・共通部門大会講演論文集 = Proceeding of Annual Conference of Fundamentals and Materials Society, IEE Japan, 2001, 159, 164, 21 Sep. 2001
Japanese - Deposition and Characterization of C:F Films Using C_7F_<16> : Effect of Material Gas Pressure and Gas Additions
HOKOI K., AKAZAWA M., SUGAWARA H., SUDA Y., SAKAI Y., 電気学会研究会資料. ED, 放電研究会, 2001, 111, 13, 18, 07 Aug. 2001
Japanese - Modeling of Carbon Plume Generation by Laser Ablation : Dependence of Ablation Rate on Laser Fluence
MATSUDA Hiroyuki, SUGAWARA Hirotake, SUDA Yoshiyuki, SAKAI Yosuke, 電気学会研究会資料. ED, 放電研究会, 2001, 111, 1, 6, 07 Aug. 2001
Japanese - An analysis of Coulomb Crystal Behavior in RF Ar Plasma under Laser Irradiation
TOMITA Ken, SUDA Yoshiyuki, SUGAWARA Hirotake, SAKAI Yosuke, 電気学会研究会資料. ED, 放電研究会, 2001, 111, 7, 12, 07 Aug. 2001
Japanese - Future Computer Simulations of Electric Discharges
SUGAWARA Hirotake, 電気学会研究会資料. ED, 放電研究会, 2001, 64, 3, 6, 07 Mar. 2001
Japanese - Effect of excitation transfer from Ar to Xe in Ne/Ar/Xe mixtures for plasma display panels
Satoshi Uchida, Hirotake Sugawara, Yosuke Sakai, Tsuneo Watanabe, SID Conference Record of the International Display Research Conference, 877, 880, 2001, [Peer-reviewed] - Effects of Accumulated Surface Charge on Dielectric Barrier Discharge : One-dimensional Fluid Model Simulation
SUGAWARA Hirotake, ODA Akinori, SAKAI Yosuke, Proceedings of the Institute of Electrostatics Japan, 24, 5, 232, 235, 30 Sep. 2000
静電気学会, Japanese - 1D fluid modeling of Xe/Ar/Ne filled PDP
BORCOMAN Ioan-Calin, ODA Akinori, SUGAWARA Hirotake, SAKAI Yosuke, UCHIDA Satoshi, 電気学会基礎・材料・共通部門大会講演論文集 = Proceeding of Annual Conference of Fundamentals and Materials Society, IEE Japan, 2000, 273, 278, 07 Sep. 2000
English - 三種希ガス混合における放電開始電圧および紫外線発光効率の検討
内田諭, 菅原広剛, 酒井洋輔, 渡辺恒雄, 電気学会基礎・材料・共通部門大会講演論文集, 2000, 2000 - PDP放電諸特性に対する非平衡領域の影響
内田諭, 菅原広剛, 酒井洋輔, 渡辺恒雄, 電気学会全国大会講演論文集, 2000, 1, 2000 - Modeling of Corona Discharge in Air(II) : Introduction of Multigrid Method into Poisson's Equation
TAKAHASHI Yoshikazu, SUGAWARA Hirotake, SAKAI Yosuke, 電気学会基礎・材料・共通部門大会講演論文集 = Proceeding of Annual Conference of Fundamentals and Materials Society, IEE Japan, 1999, 206, 211, 08 Sep. 1999
Japanese - On Vector Loci of the Electron Drift Velocity in E×B Fields in Constant-Collision-Frequency Model
SUGAWARA Hirotake, YAHATA Takashi, SAKAI Yosuke, 電気学会基礎・材料・共通部門大会講演論文集 = Proceeding of Annual Conference of Fundamentals and Materials Society, IEE Japan, 1999, 229, 229, 08 Sep. 1999
Japanese - Analyses of electron transport coefficients in E×B fields in reactive gases
YAHATA Takashi, SUGAWARA Hirotake, SAKAI Yosuke, 電気学会研究会資料. ED, 放電研究会, 1999, 46, 13, 18, 05 Aug. 1999
Japanese - Excited atomic oxygen density distribution in a discharge obtained by laser absorption spectroscopy
OHKUBO Mitsuyuki, KAMADA Takehiro, BRATESCU Maria-Antoaneta, SAKAI Yosuke, SUGAWARA Hirotake, 電気学会研究会資料. ED, 放電研究会, 1999, 46, 37, 42, 05 Aug. 1999
Japanese - Effects of Impulse Field on Electron Acceleration in RF Plasmas
SHIMODA Takuro, SUGAWARA Hirotake, SAKAI Yosuke, 電気学会研究会資料. ED, 放電研究会, 1999, 46, 61, 66, 05 Aug. 1999
Japanese - Deposition of fluorocarbon polymer films in plasma excited by DC discharge and UV radiation
CP Lungu, AM Lungu, Y Sakai, H Sugawara, M Tabata, INTERNATIONAL CONFERENCE ON PHENOMENA IN IONIZED GAS, VOL I, PROCEEDINGS, 43, 44, 1999, [Peer-reviewed]
English - Spatial and temporal distribution of species in a plasma excited by dc discharge and UV irradiation applied for NO2 decomposition
CP Lungu, AM Lungu, G Inoue, Y Sakai, H Sugawara, INTERNATIONAL CONFERENCE ON PHENOMENA IN IONIZED GAS, VOL I, PROCEEDINGS, 97, 98, 1999, [Peer-reviewed]
English - Decomposition of NO_2 by hybrid method of the DC discharge and the UV irradiation : Effect of He, N_2, O_2 admixtures
INOUE G., LUNGU C. P., LUNGU A., SUGAWARA H., SAKAI Y., 電気学会研究会資料. ED, 放電研究会, 1998, 69, 31, 36, 31 Jul. 1998
Japanese - Modeling of Xenon Excimer Lamp Barrier Discharges : A Study on Simulation Model of Discharges between Electrodes covered Dielectric Barrier
ODA Akinori, Sugawara Hirotake, Sakai Yosuke, Akashi Haruaki, Proceeding of Annual Conference of The Illuminating Engineering Institute of Japan, 31, 85, 85, 22 Jul. 1998
The Illuminating Engineering Institute of Japan (IEIJ), Japanese - Centroid drift velocity of electron swarms in gases
Hirotake Sugawara, Hiroaki Tagashira, Yosuke Sakai, Electrical Engineering in Japan, 122, 1, 1, 7, 15 Jan. 1998
English - レーザ分光法による非平衡プラズマの診断 (IX) Xe/Neプラズマ中の励起原子数密度空間分布のシミュレーション
内田諭, 菅原広剛, 酒井洋輔, 電気学会全国大会講演論文集, 1998, 1, 1998 - CCl2F2電子衝突断面積の推定
深谷昌史, 内田諭, 菅原広剛, 酒井洋輔, 電気学会全国大会講演論文集, 1998, 1, 1998 - A Boltzmann equation analysis of electron swarm parameters and properties of excited particle number densities in Xe/Ne plasmas - laser absorption effect -
内田論, 菅原広剛, VENTZEK P L G, 酒井洋輔, The Transactions of The Institute of Electrical Engineers of Japan, 118-A, 6, 622, 628, 1998 - A Two-Dimensional Monte Carlo Simulation of Ar Plasmas : Effects of Plasmaes for Electrode and Bessele
YOSHIDA Jun, ODA Akinori, SUGAWARA Hirotake, VENTZEK P. L. G., SAKAI Yosuke, 電気学会研究会資料. ED, 放電研究会, 1997, 167, 97, 102, 18 Nov. 1997
Japanese - Analysis of a micro-discharge in a Xe Barrier Discharge Excited Excimer Lamp
ODA Akinori, SUGAWARA Hirotake, VENTZEK Peter L. G., SAKAI Yosuke, AKASHI Haruaki, 電気学会研究会資料. ED, 放電研究会, 1997, 167, 85, 90, 18 Nov. 1997
Japanese - Effect of the Electron Diffusion Coefficients on Gaussian Development of Electron Swarms in Real Space
SUGAWARA Hirotake, SAKAI Y., TAGASHIRA H., KITAMORI K., 電気学会研究会資料. ED, 放電研究会, 1997, 167, 61, 66, 18 Nov. 1997
Japanese - A Boltzmann Equation Analysis of Electron and Excited Particle Properties in Xe/Ne Plasmas : Laser Absorption Effect
UCHIDA Satoshi, SUGAWARA Hirotake, VENTZEK Peter L. G., SAKAI Yosuke, 電気学会研究会資料. ED, 放電研究会, 1997, 167, 67, 72, 18 Nov. 1997
Japanese - A Simulation of Xe Excimer Lamp Barrier Discharges : Influence of Power Frequency and Gas Pressure on Dielectric Barrier Discharge Characteristics
ODA Akinori, SUGAWARA Hirotake, VENTZEK P. L. G., SAKAI Yosuke, AKASHI Haruaki, 電気学会研究会資料. ED, 放電研究会, 1997, 83, 55, 60, 06 Aug. 1997
Japanese - A Boltzmann Equation Analysis of Electron Swarm Parameters in Xe/Ne Mixtures Considering Reactions of Excited Particles.
内田諭, 菅原広剛, VENTZEK P L G, 酒井洋輔, 電気学会放電研究会資料, ED-97, 83-95, 1997 - Non Equilibrium Plasma Diagnostics by Laser Spectroscopy. (VIII). A Simulation of Spatial Change in Electron Density by Laser Irradiation.
内田諭, 菅原広剛, VENTZEK P L G, 酒井洋輔, 電気学会全国大会講演論文集, 1997, 1, 1997 - A Simulation of Xe Excimer Lamp Discharge : RF Barrier Discharge Plasma
ODA Akinori, SUGAWARA Hirotake, VENTZEK Peter L. G., SAKAI Yosuke, AKASHI Haruaki, 電気学会研究会資料. ED, 放電研究会, 1996, 218, 29, 38, 27 Nov. 1996
Japanese - The Centroid Drift Velocity of Electron Swarms in Gases : Derivation using Moment Equations Described in Velocity Space
SUGAWARA H, TAGASHIRA H, SAKAI Y, 電気学会研究会資料. ED, 放電研究会, 1996, 218, 1, 10, 27 Nov. 1996
Japanese - Ion Velocity Distribution under Constant-Collision-Frequency Symmetric Charge Exchange Model
SUGAWARA H, TAGASHIRA H, SAKAI Y, 電気学会研究会資料. PST, プラズマ研究会, 1996, 64, 73, 82, 08 Aug. 1996
Japanese - Modeling of Non-Equilibrium Radio-Frequency Glow Discharge Plasma Step-Response of Radio-Frequency Capacitively Coupled Discharges
YANG Jing, SUGAWARA H., VENTZEK Peter, SAKAI Y., TAGASHIRA H., 電気学会研究会資料. PST, プラズマ研究会, 1996, 64, 55, 61, 08 Aug. 1996
Japanese - Non Equilibrium Plasma Diagnostics by Optogalvanic Spectroscopy. (VII). Dependence of Plasma Parameters on photon density.
内田諭, 菅原広剛, VENTZEK P L G, 酒井洋輔, 電気関係学会北海道支部連合大会講演論文集, 1996, 1996 - Non Equilibrium Plasma Diagnostics by Optogalvanic Spectroscopy. (VI). Analysis of OG Signals in Ne Plasma by Propagator Method.
内田諭, 菅原広剛, VENTZEK P L G, 酒井洋輔, 田頭博昭, 電気学会全国大会講演論文集, 1996, 1, 1996 - Modeling of OG Effect in Discharge Plasma. Analysis of Ne discharge Plasma by Propagator Method.
内田諭, 菅原広剛, VENTZEK P L G, 酒井洋輔, 電気学会放電研究会資料, ED-96, 218-224.226-239.241.243-254, 1996 - Simulation of plasma diagnostics by using the OG spectroscopy.
内田諭, 菅原広剛, VENTZEK P, 酒井洋輔, 田頭博昭, 電気学会放電研究会資料, ED-95, 117-129, 1995 - Non-equilibrium Plasma Diagnostics by Optogalvanic Spectroscopy. (III). Change of Electron Density in Positive Column by Laser Radiation.
内田諭, 菅原広剛, VENTZEK P, 酒井洋輔, 田頭博昭, 電気学会全国大会講演論文集, 1995, 1, 1995 - Swarm Parameters in Gases. (CCXXXVII). Modeling of Positive Column by a Propagator Method.
菅原広剛, 内田諭, 酒井洋輔, 田頭博昭, 電気学会全国大会講演論文集, 1995, 1, 1995 - Plasma Diagnostics by Optogalvanic Spectroscopy. (IV). Analysis of OG Signals by Propagator Method.
内田諭, 菅原広剛, VENTZEK P L G, 酒井洋輔, 田頭博昭, 電気関係学会北海道支部連合大会講演論文集, 1995, 1995
Books and other publications
- 電気学会技術報告第1488号「放電・プラズマ気相シミュレーション技法」
放電・プラズマ気相シミュレーション技法調査専門委員会編, 菅原広剛, 調, 委員会委員長, 1.1節「電子エネルギー分布・速度分布計算法1:ボルツマン方程式解析」1.2節「電子エネルギー分布・速度分布計算法2:モンテカルロ法」1.3節「電子エネルギー分布・速度分布計算法3:プロパゲータ法」
社団法人電気学会, 17 Jun. 2020, [Contributor] - 電気学会技術報告第1185号「放電基礎パラメータと放電応用技術の最前線」
菅原 広剛, 2.2.1節「プロパゲータ法による電子スオーム解析」、2.2.2節「モンテカルロ法における電子衝突判定の高速化」
社団法人電気学会, Apr. 2010, [Contributor] - 電気学会技術報告第1061号「窒素の放電プラズマが見せる多様性と最新応用」
菅原 広剛, 5章1節「N2およびSF6/N2混合ガス中の電子衝突過程と電子エネルギー分布」
社団法人電気学会, Aug. 2006, [Contributor]
Lectures, oral presentations, etc.
- Electron Energy Gain Mechanisms near Chamber Wall in Inductively Coupled Magnetized Plasmas under Different Gas Pressures
H. Takahashi, H. Sugawara
The 11th Asia-Pacific International Symposium on the Basics and Applications of Plasma Technology, 30 Dec. 2019, English, Poster presentation
10 Dec. 2019 - 14 Dec. 2019, 13888736 - Vector loci of average electron velocity in gases under ac electric and dc magnetic fields
H. Sugawara, T. Sato, Y. Nakata
The 11th Asia-Pacific International Symposium on the Basics and Applications of Plasma Technology, 13 Dec. 2019, English, Poster presentation
10 Dec. 2019 - 14 Dec. 2019, 13888736 - Investigation of mobility spectra obtained by mobility measurement and simulation in different-purity O2 gases
Y. Okuyama, K. Ikeda, H. Sugawara
The 11th Asia-Pacific International Symposium on the Basics and Applications of Plasma Technology, 12 Dec. 2019, English, Oral presentation
10 Dec. 2019 - 14 Dec. 2019 - Response of Average Electron Velocity Vector under AC Electric and DC Magnetic Fields in a Constant-Collision-Frequency Model
H. Sugawara
Proc. 72nd Annual Gaseous Electronics Conference, Oct. 2019, English
Oct. 2019 - Oct. 2019 - Quantification of electron confinement effect under confronting divergent magnetic fields considering mutual electron transfer across separatrix
R. Ozawa, H. Sugawara
Proc. XXXIV International Conference on Phenomena in Ionized Gases, 10th International Conference on Reactive Plasmas, 37th Symposium on Plasma Processing, and 32nd Symposium on Plasma Science for Materials, Jul. 2019, English
Jul. 2019 - Jul. 2019 - Electron energy gain mechanisms near chamber wall in inductively coupled magnetized plasmas
H. Takahashi, H. Sugawara
Proc. XXXIV International Conference on Phenomena in Ionized Gases, 10th International Conference on Reactive Plasmas, 37th Symposium on Plasma Processing, and 32nd Symposium on Plasma Science for Materials, Jul. 2019, English
Jul. 2019 - Jul. 2019 - Evaluation of electron drift velocity vector in gas under RF electric and DC magnetic fields
T. Sato, H. Sugawara
Proc. XXXIV International Conference on Phenomena in Ionized Gases, 10th International Conference on Reactive Plasmas, 37th Symposium on Plasma Processing, and 32nd Symposium on Plasma Science for Materials, Jul. 2019, English
Jul. 2019 - Jul. 2019 - The comparison between experimental and simulation results of negative ion mobility in O2 in relation to reduced electric field intensity
K. Ikeda, Y. Okuyama, H. Sugawara
Proc. XXXIV International Conference on Phenomena in Ionized Gases, 10th International Conference on Reactive Plasmas, 37th Symposium on Plasma Processing, and 32nd Symposium on Plasma Science for Materials, Jul. 2019, English
Jul. 2019 - Jul. 2019 - Configuration of propagator method for calculation of electron velocity distribution function in gas under crossed electric and magnetic fields
SUGAWARA Hirotake
The 19th Asian Conf. on Electrical Discharge, 24 Nov. 2018, English, Invited oral presentation
Xianyang, Shaanxi, China, [Invited], [International presentation] - Monte Carlo analysis of the asymmetry in azimuthal electron flow in an inductively coupled plasma driven under confronting divergent magnetic fields
菅原 広剛
XXIV Europhysics Conf. on Atomic and Molecular Physics of Ionized Gases, 17 Jul. 2018, English, Poster presentation
Glasgow, Scotland, UK, [International presentation] - Computational Study on Characteristic Mechanisms of Energy Deposition to Electrons in a Low-Pressure Inductively Coupled Magnetized Plasma
菅原 広剛
20th Gaseous Electronics Meeting, 22 Jun. 2018, English, Invited oral presentation
Magnetic Island, Townsville, Australia, [Invited], [International presentation] - Calculation of Real-Space Electron Transport Coefficients under Crossed Electric and Magnetic Fields by a Propagator Method
菅原 広剛
10th Asia-Pacific Int. Symp. on the Basics and Applications of Plasma Technol., 15 Dec. 2017, English, Invited oral presentation
Chung Yuan Christian University, Taoyuan, Taiwan, [Invited], [International presentation] - Calculation of electron velocity distribution function under crossed electric and magnetic fields using a propagator method
菅原 広剛
XXXIII Int. Conf. Phenomena in Ionized Gases, 09 Jul. 2017, English, Poster presentation
Estoril/Lisboa, Portugal, [International presentation] - Fundamental study on filter effect of confronting divergent magnetic fields applied to a low-pressure inductively coupled plasma
SUGAWARA Hirotake
9th Int. Conf. Reactive Plasmas/68th Ann. Gaseous Electronics Conf./33rd Symp. Plasma Processing, 14 Oct. 2015, English, Invited oral presentation
[Invited], [International presentation] - Electron conduction under the rectification effect of antiparallel magnetic fields
SUGAWARA Hirotake
XVI Int. Workshop on Low-Energy Positron and Positronium Physics & XVII Int. Symp. on Electron-Molecule Collisions and Swarms, 19 Jul. 2015, English, Invited oral presentation
Maynooth, Ireland, [Invited], [International presentation] - Monte Carlo simulation of electron motion in confronting divergent magnetic fields
SUGAWARA Hirotake
XXXI Int. Conf. Phenomena in Ionized Gases, 14 Jul. 2013, English, Poster presentation
[International presentation] - Stochastic scattering process to induce inward electron flow in electron conduction path between antiparallel gradient magnetic fields
SUGAWARA Hirotake
XXI Europhysics Conf. on Atomic and Molecular Physics of Ionized Gases, 10 Jul. 2012, English, Poster presentation
[International presentation] - 不平等磁界下の電子輸送
菅原 広剛
原子分子データ応用フォーラムセミナー・核融合科学研究所原子分子データと原子分子過程モデルの活用・普及研究会, 13 Dec. 2011, Japanese, Invited oral presentation
[Invited], [Domestic Conference] - Monte Carlo simulation of electron transport under quadrupole magnetic field and radio-frequency electric field
SUGAWARA Hirotake
30th Int. Conf. Phenomena in Ionized Gases, 28 Aug. 2011, English, Poster presentation
[International presentation] - Electron conduction under the rectification effect of antiparallel magnetic fields
Hirotake Sugawara
XVI Int. Workshop on Low Energy Positron and Positronium Physics & XVII Int. Symp. Electron-Molecule Collisions and Swarms, Jul. 2011, English
Jul. 2011 - Jul. 2011, [Invited] - Electron drift along magnetically neutral channels between gradient magnetic fields
SUGAWARA Hirotake
15th Gaseous Electronics Meeting, 05 Feb. 2008, English, Invited oral presentation
Murramarang Resort, Australia, [Invited], [Domestic Conference] - Electron acceleration under short intense impulse electric fields
SUGAWARA Hirotake
XVth Int. Conf. on Gas Discharges and their Applications, 09 Sep. 2004, English, Invited oral presentation
Toulouse, France, [Invited], [International presentation] - Control of selectivity in electron-molecule reactions by impulse field electron acceleration
SUGAWARA Hirotake
Int. Symp. on Electron-Molecule Collisions and Swarms, 19 Jul. 1999, English, Invited oral presentation
The Waterfront Town, Tokyo, Japan, [Invited], [International presentation] - Electron behavior under characteristic magnetic fields applied to inductively coupled plasmas for control of charged particle transport
SUGAWARA Hirotake
XVIII Int. Workshop on Low-Energy Positron and Positronium Physics (POS) & XIX Int. Symp. on Electron-Molecule Collisions and Swarms (EMS), English, Invited oral presentation
[Invited], [International presentation]
Courses
Affiliated academic society
Research Themes
- Computer simulation of enhancement of electron heating by partial resonance under high-frequency driving of inductively coupled magnetized plasmas
Grants-in-Aid for Scientific Research
01 Apr. 2024 - 31 Mar. 2027
菅原 広剛
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 24K07448 - Computational analyses on asymmetric directional electron transport and partial resonance originating in the arrangement of electric and magnetic fields in inductively coupled magnetized plasmas
Grants-in-Aid for Scientific Research
01 Apr. 2019 - 31 Mar. 2022
SUGAWARA HIROTAKE
Electron motion in magnetized plasmas for material processing was simulated focusing on the partial resonance as a process of the electron energy gain (EEG). Fundamental understanding for design and control of practical plasma reactors was obtained by evaluation of the EEG under various arrangements of the magnetic coils, the power-source antenna and the magnetic field strengths. New measures for the EEG and the asymmetry of electron flow caused by the arrangement of the electric and magnetic fields were introduced as weighting various effects of the parameters determining the electron motion. This simplified the seeking task for desirable conditions for the partial resonance. The ac response of the average electron velocity vector, that governs the EEG and the directional electron flow, was analyzed under field conditions extended to arbitrary angles between the electric and magnetic fields. Its basic features were validated by a theory based on a constant-collision-frequency model.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, Principal investigator, Competitive research funding, 19K03780 - Analysis of energy-selective shutter and filter effects of separatrix of confronting divergent magnetic fields on electrons in plasma
Grants-in-Aid for Scientific Research
01 Apr. 2016 - 31 Mar. 2019
Sugawara Hirotake
Behavior of electrons and ions in low-pressure inductively coupled plasmas under confronting divergent magnetic fields (CDMFs) was analyzed using computer simulations based on a Monte Carlo method to reveal the mechanism of the shutter and filter effects of the separatrix of the CDMSs, that confine electrons and limit the flow of electrons by their energy and to search for their applications to downsizing of plasma reactors and damage-free material processing.
A method to quantify the confinement effect was proposed and the contribution of the confinement to ionization was confirmed. Three modes of the power deposition to electrons under the CDMFs were observed as main mechanisms to sustain the plasma. Fundamental tendencies of ion transport to the substrate were observed in various setups as informative bases for design and control of the plasma reactors. A new calculation technique for the electron transport coefficients under crossed electric and magnetic fields was also developed.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, Principal investigator, Competitive research funding, 16K05626 - Computational analysis of reactive particle flow in inductively coupled processing plasmas under confronting divergent magnetic fields
Grants-in-Aid for Scientific Research
01 Apr. 2013 - 31 Mar. 2016
Sugawara Hirotake
Confronting divergent magnetic fields (CDMFs) divide an inductively coupled processing plasma into two parts of high and low plasma densities by suppressing electron diffusion. This effect was analyzed by computer simulations of electron motion.
The electron confinement by the separatrix of the CDMFs was confirmed to occur with electron capture by magnetic flux lines. In addition, it was found that a significant electron energy gain by the electron cyclotron resonance occurred even in a region far from the radio-frequency (rf) antenna used to drive the plasma.
The electron confinement worked well under strong magnetic fields, and the electron passage across the separatrix was energy-dependent. That across the outer separatrix tended to occur for high-energy electrons. On the other hand, that via the weak magnetic field (a magnetic aperture) inside the rf-resonant region was allowed even for low-energy electrons. An application of the separatrix as a magnetic shutter was proposed.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, Principal investigator, Competitive research funding, 25400528 - Spin-polarized Lasing in Quantum Dots
Grants-in-Aid for Scientific Research
01 Apr. 2010 - 31 Mar. 2015
MURAYAMA Akihiro, SUEOKA Kazuhisa, SUGAWARA Hirotake
We have studied spin-polarized lasing, which can transform electron-spin information into circular polarization properties in stimulated emission, by employing III-V compound semiconductor quantum dots (QDs) exhibiting strong suppression of spin relaxation.
Spin-injection dynamics and spin relaxation in QDs in addition to fabrication processes of QDs have been studied for the purpose of temporal spin storage during the emission. We show that Pauli spin blocking is a major factor of spin loss during the spin injection into QDs. To resolve this issue, we conclude that high density QDs and tunneling of spins from two-dimensional electron systems realize highly efficient and ultrafast spin injection into QDs. QD light emitting diodes with active layers composed of QDs and metallic ferromagnetic spin electrodes have been fabricated, which indicates circularly polarized electroluminescence reflecting efficient electron-spin injection.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (S), Hokkaido University, 22221007 - Modeling of low-pressure high-density magnetic neutral loop discharge processing plasmas and analysis of their dynamic control
Grants-in-Aid for Scientific Research
2010 - 2012
SUGAWARA Hirotake
Computer simulations of magnetic neutral loop discharge plasmasused for surface processing in fabrication of semiconductor integrated circuits have beenperformed. It was revealed that high-energy electrons were transported along theseparatrix of the magnetic field and generated reactive species there by dissociationof the medium gas. The flux of the reactive species on the semiconductor substrate washigh at the foot of separatrix. This result explained early experimental data well. Acontrol scheme for uniform wide-area processing by moving the foot of separatrix overthe substrate was proposed.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 22540500 - Deposition of hetero-structure layered low-k amorphous fluorinated carbon films under sequence control of gas feed and plasma power
Grants-in-Aid for Scientific Research
2007 - 2009
SUGAWARA Hirotake, SUDA Yoshiyuki
Amorphous fluorocarbon (a-C:F) films, which are applicable to insulation of electrical power equipment and integrated circuits, were deposited by plasma-enhanced chemical vapor deposition using a C_8F_<18> feedstock. When the a-C:F films were composed at a low plasma power, the thermal tolerance of the films was weak for less bondings between molecular chains in the a-C:F films (loose films). The dielectric constant of these a-C:F films had a tendency to be lower than that of conventional a-C:F films with dense bondings between molecular chains (firm films). This feature is desirable for reduction of the dielectric energy loss in power equipment and the delay of the signal transmission in the integrated circuits. In addition, we found a waving phenomenon of the firm film due to the heat given during the deposition of the firm film on a loose film. The voids made under the wavy film are also expected to contribute to the reduction of the dielectric constant of the a-C:F films.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 19540517 - Selective growth of metallic/semiconducting single-walled carbon nanotubes by precise supply control of chemically active species
Grants-in-Aid for Scientific Research
2007 - 2008
SUDA Yoshiyuki, SUGAWARA Hirotake, TAKAYAMA Junichi
(1) カーボンナノチューブ(CNT)の原料ガスであるCH_4にCO_2ガスを添加したところ,多層CNTの層数・内径・外径が増加した。また,CO_2添加により単層CNTの直径分布を太い方へ変化できた。(2)CNT成長領域から60cm程度の距離にプラズマを発生させることで,Si基板上に堆積したAl_2O_3/Fe/Al_2O_3の3層構造触媒から欠陥のほとんどない高品質な単層CNTが合成できた。
Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists (B), 19740339 - COMPACT AND HIGH DIELECTRIC STRENGTH OF ELECTRIC MACHINES WITH a-C:F FILM COATING OF LOW-DIELECTRIC CONSTANT AND HIGH DIELECTRIC STRENGTH DEPOSITED IN PLASMA
Grants-in-Aid for Scientific Research
2005 - 2007
SAKAI Yosuke, SUGAWARA Hirotake, SUDA Yoshiyuki
SF_6 gas shows excellent properties as an electric insulating material, however as it's global warming factor is extremely big, the gas is now forbidden to be exhausted outdoors. The present research is, in place of SF_6 gas usage, to propose an alternative technique that conductor parts, which are coated by amorphous carbon-fluoride (a-C:F) film processed in plasma, are introduced in a gas insulation system. Then, the air breakdown voltage between the coated electrodes was shown to be the same level or even higher than that of SF_6 gas between the conventional electrodes.
The main results are summarized as follow, 1) a-C:F film with a few hundred nanometers thickness was coated, in a chemically and physically stable condition, on the surface of spherical metal electrodes, 2) the present film was shown to be a tetrafluoroethylene (PTFE) like film with a low dielectric constant and high breakdown strength as a result of the analyses by SEM, XPS, FTIR and others, 3) the gas breakdown voltage in the Paschen curve, in which the breakdown voltage is given as a function of pd (p: gas pressure and d: gap length), in the present electrodes was the same level as the case of SF_6 in the conventional electrode system, 4) the surface condition of a-C:F film depended on the amount of buffer gases (Ar, He) in the RF plasma. In addition, assuming breakdown of a part of the film, re-deposition of a-C:F film was tried on the original surface, then, 4) double layers and triple layers, in the case of second and third times deposition, were clearly obtained. And in the case of the third times deposition, on the surface an interesting regularly patterned figures appeared.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 17360121 - 衝撃電界重畳高周波プラズマによるフッ化炭素プロセス排ガス分解除害効率の計算機解析
科学研究費助成事業
2004 - 2006
菅原 広剛
本研究は、集積回路製造工程で排出されるフルオロカーボンであるCF_4地球温暖化ガスを非平衡プラズマにより効率的に分解する方法として選択的分解反応促進が期待されるプラズマへの衝撃電界重畳を提案し解析するものである。衝撃電界により電子した電子の衝突過程の計算機解析による定量的評価を中心として、以下1〜3の結果を得た。
1.衝撃電界下の電子の挙動解析とエネルギー効率の評価:
衝撃電界で与える電子加速量を変化させ、共にCF_4分解に寄与する中性解離と電離性解離のエネルギー消費割合をモンテカルロ法で計算・比較した。加速量増加に伴い閾値の大きな電離性解離に費やされるエネルギー割合が単調増加し、中性解離の割合は飽和傾向を示した。プラズマ維持と解離促進を同時に図るためには電離性解離の閾値を超える高エネルギー領域にまで電子を加速することが必要で、この点で衝撃電界電子加速が有効と考えられる。
2.CF_4ラジオ周波数プラズマ解析系構築と新高速衝突判定法の提案:
電極を含む系でCF_4プラズマ中の解離生成種の生成頻度と空間分布とを統計的に安定に扱う手法を提案した。また計算負荷となっていたCF_4分子と電子との衝突判定において、無衝突となる場合を効率よく検出し電子衝突断面積計算を省く新高速判定法を提案した。これにより電子追跡に要する計算負荷を著しく軽減させ、追跡電子数増や長時間計算、また混合ガスへの対応を容易にした。
3.CF_4中電子輸送過程:
CF_4中の電子加速時初期緩和過程に見られる空間分布の複数ピーク形状と電子輸送係数の緩和過程を解析した。研究者間で想定が異なる電子衝突断面積構成により空間分布、電子輸送係数とも差異が生じた。衝撃電界電子加速の制御性評価の際は特に、加速途中で電子の集団性を失わせる低・中エネルギー部の電子衝突断面積構成への依存性が大きいと考えられる。
主な結果は研究発表欄の論文として公表した。
日本学術振興会, 若手研究(B), 北海道大学, 16760216 - 電力機器用絶縁気体混合相乗効果の微視的定量的計算機解析
科学研究費助成事業
2002 - 2003
菅原 広剛
地球温暖化防止のためのSF_6絶縁ガス使用量低減に向け、SF_6をN_2他で希釈した際に現われる絶縁特性相乗効果発生機構を混合ガス中の電子エネルギー損失過程と電子捕獲機構の面から解析した。
平成15年度は、電子のエネルギー損失過程および衝突間の電子挙動に関する14年度の解析結果を踏まえ、既に構築済みの計算機プログラムを用いて、電子衝突断面積の組み合わせの効果を主にSF_6/N_2、SF_6/CO_2、SF_6/c-C_4F_8の3つの混合ガスの比較を通じて解析した。解析結果は次のようにまとめられる。
SF_6/N_2混合ガス中では、電子はN_2との衝突によりエネルギーを失って低エネルギーとなり、2〜3eV付辺に存在するN_2の弾性衝突および振動励起衝突の断面積ピークに起因するバリア効果(電子エネルギー上昇を妨げる)によって低エネルギー状態に保たれその間にSF_6により捕獲されることが電子衝突履歴の追跡により確認できた。
SF_6/CO_2でもCO_2のバリア効果が見られるが、CO_2はN_2に比べバリアが低く高エネルギー寄りに位置することから電子を低エネルギー域に閉じ込め付着を促す働きはSF_6/N_2ほど強くない。N_2とCO_2についてはバリア効果の強弱とSF_6との相乗効果の程度は大小関係が一致しており、この種の混合ガスの相乗効果はバリア効果によるものと推測された。
SF_6/c-C_4F_8混合ガスにおいては、c-C_4F_8の電子励起衝突断面積の立ち上がりが急なことが励起の閾値付近での衝突を起こり易くし、励起衝突直後の電子エネルギーを低くする結果をもたらす。SF_6の電子付着は低エネルギーほど起こり易いため、閾値近くの励起衝突が直接電子付着に結びつくためと考えられる。
日本学術振興会, 若手研究(B), 北海道大学, 14750200 - Development of insulating system with low dielectric constant, high dielectric strength a-C:F film coated conductor prepared by plasma CVD as alternatives to SF_6
Grants-in-Aid for Scientific Research
2001 - 2003
SAKAI Yosuke, SUDA Yoshiyuki, AKAZAWA Masamichi, SUGAWARA Hirotake, NAKAJIMA Masatoshi, BRATESCU A. maria
In order to reduce the usage of SFs insulation gas, which has high GWP (global warming potential), the present project proposed to use a-C:F film coated conductor prepared by RF plasma CVD method for insulation of electric power systems as alternatives of SF_6. This project was motivated because we had experienced very high deposition rates in RF plasma if per-fluorocarbon vapors were used. The main results are listed as follows.
l. The deposition rate on Si and A1 substrates was > 100-200nm/min, which is a few tens times higher than those obtained by conventional CF_4 and C_2F_6 gases.
2. The a-C:F film, which is composed of C-C and C-F bonds, was excellent insulation properties (dielectric constant 【approximately equal】 2) with high density and good thermal strength.
3. The breakdown voltage V_s of N_2, Ar and He between the a-C:F film coated Al electrodes were 3 times larger than that between Al ones in low p(pressure)d(gap length) region. For pd<20 Torr/cm the V_s was rather higher than that of SFs.
4. Reason of the enhancement of V_s was explained by the fact that secondary electron emission rate was reduced significantly by this film coating.
5. Effect of decomposed species in the plasma on the a-C:F film properties was tried to examine, but in this project term it was not really cleared.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), HOKKAIDO UNIVERSITY, 13555077 - 高耐力フルオロカーボン絶縁被覆のプラズマプロセスによる形成と損傷修復に関する研究
科学研究費助成事業
2000 - 2001
菅原 広剛
C_7F_<16>を材料としたプラズマCVD法でアモルファスフルオロカーボン(CF)膜を堆積した。XPSでF/C組成比を、静電容量測定とエリプソメータによる膜厚測定から比誘電率ε_rを、正極性針対平板電極系絶縁破壊試験で絶縁耐力をそれぞれ測定し、熱処理(100〜300℃)後の膜厚減少分から耐熱性を評価した。これらの結果から(1)材料のガス圧依存性(30〜80Pa)、(2)He混合(0〜30Pa)の影響、(3)酸素混合(2〜4Pa)の影響を検討した。
(1)では低圧ほどF/C比が上昇しε_rは2.1程度まで下がったが、同時に堆積率も低下し耐熱性試験時の膜厚減少幅も大きくなった。絶縁耐力は2MV/cm以上であった。材料ガス圧による膜質制御では耐熱性向上と誘電率低減の両立は難しかった。類似の巨大分子材料C_8F_<18>を用いて堆積したCF膜でも比誘電率は2.5以下、絶縁耐力は1MV/cm以上であった。
(2)ではHe増加に伴いε_rが低下し(1)同様の傾向が見られた。加えて、堆積中のプラズマ状態が安定して膜質のばらつきが減り再現性が向上した。
(3)ではCF膜からのC原子引き抜きによるF/C比増加即ちε_r低下を期待したが、酸素活性種のエッチング効果が強く数Paの混合で堆積率が著しく低下し、6Pa以上では膜堆積できなくなった。2〜4Paにおける堆積膜の膜質はばらつきが大きいものの、中には低いε_rが得られた例もあり、多孔質構造のような空疎なCF膜が得られた可能性が示唆される。
続いて、絶縁破壊部再生を模擬し、CF膜で被覆済みの面と基板が露出した面が接する個所へのCF膜再堆積を試みた。膜厚の時間変化から、再堆積開始時は露出面への堆積の方が速やかに進む傾向が見られたが、再堆積が進行した後は、被覆面と露出面に堆積したCF膜の厚さは同程度になった。
日本学術振興会, 奨励研究(A), 北海道大学, 12750233 - 衝撃電解重畳法によるフロン分解の大体積化および選択的分解反応促進に関する基礎研究
科学研究費助成事業
1998 - 1999
菅原 広剛
RF(13.56MHz)非平衡放電プラズマに衝撃電界を重畳することによりプラズマ中の電子を短時間のうちに揃って加速し、単一エネルギー的な電子群を生成してフロン12の分解反応の選択性、効率の向上とバルク領域での大体積分解反応の促進を図る技法を流体コードを用いて計算機解析した。
衝撃電界を印加するとプラズマシースの厚さが変化してこれを吸収してしまうため、衝撃電界がバルク領域に到達する時間は限られるが、誘電緩和時間の見積りや数値解析の結果、数ns程度の間は衝撃電界を維持でき、電子エネルギーをフロン12解離のしきい値(中性解離7.2eV、解離性電離12.2eV以上)まで高めることができた。フロン12は高エネルギー領域で中性解離・解離性電離、低エネルギー領域で解離性付着の衝突断面面積を持ち、これらは共に分解反応に寄与する。しかし低エネルギー領域での電子付着が大きいと放電維持が困難になることから、解離性電離を選択的に促進し分解処理と放電維持を同時に図るのが効果的である。
バルク領域へ到達する衝撃電界の大きさは衝撃電界の立ち上がり時間に対して敏感に変化し、衝撃電界の立ち上がりが急峻な程バルクに到達する電界も大きいことが確認された。強度500V/cm、印加時間5nsの衝撃電界について立ち上がり時間を2nsから0.25nsに縮めると、分解処理量は35%程度増加した。この程度の立ち上がり時間は数kV規模の高電圧パルス発生装置で実現しているが、実際の回路では容量と抵抗を小さくしてプラズマ中に大きな変位電流が流れるようにする必要がある。衝撃電界を逆極性で印加しても同程度の電子加速効果が得られたことから考えると、衝撃電界印加は任意の方向で構わないものと思われる。したがって衝撃電界印加のための電極をRF放電駆動用電極とは別に設けて回路定数設定の自由度を高めることも可能と考えられる。
日本学術振興会, 奨励研究(A), 北海道大学, 10750201 - Basic study on decomposition of air pollutants using synergetic effect between barrier discharge and VUV light
Grants-in-Aid for Scientific Research
1997 - 1999
SAKAI Yosuke, HOUNO Hitoshi, IGARASHI Tatsushi, SUGAWARA Hirotake
Investigation on decomposition of air pollutants, such as nitrogen dioxides, fluorocarbons (CィイD27ィエD2FィイD216ィエD2, (CィイD23ィエD2FィイD27ィエD2)ィイD23ィエD2N/(CィイD24ィエD2FィイD24ィエD2)ィイD23ィエD2N or CィイD28ィエD2FィイD28ィエD2/ CィイD28ィエD2FィイD216ィエD2O), volatile chemical compounds, etc. and change them into non-harmful substances has been carried out using a hybrid method of electrical discharge and VUV light (172nm) irradiation. The discharge characteristics between barrier and corona type has been simulated in order to design an efficient decomposing system and VUV light source. The results are shown as follows,
1) NOィイD22ィエD2 with gas pressures between 1 and 3 Torr was decomposed into NィイD22ィエD2 and OィイD22ィエD2 by dc discharge, in addition, by irradiation of VUV light the decomposition speed was accelerated. The synergetic effect for the decomposition level and speed were confirmed by observation of the decomposed species by a gas chromatography, emission spectra from plasma and a quadrupole mass analysis.
2) Fluorocarbons, CィイD27ィエD2FィイD216ィエD2, (CィイD23ィエD2FィイD27ィエD2)ィイD23ィエD2N/(CィイD24ィエD2FィイD24ィエD2)ィイD23ィエD2N and CィイD28ィエD2FィイD28ィエD2/CィイD28ィエD2FィイD216ィエD2O, were decomposed by dc and rf discharge plasma. In this case no synergetic effect by VUV irradiation was seen. In a plasma phase a various kind of species, such as CF, CFィイD22ィエD2, CFィイD23ィエD2, CィイD22ィエD2FィイD23ィエD2, CィイD22ィエD2FィイD25ィエD2, CィイD23ィエD2FィイD23ィエD2, CィイD23ィエD2FィイD25ィエD2, CィイD23ィエD2FィイD26ィエD2, were observed by a mass analysis method. Some of the fragments among them were found to be captured on the electrode surface as a film.
3) On the electrode surface it was seen by XPS spectra that thin film was composed of CF, CFィイD22ィエD2, CFィイD23ィエD2 and -C-CFィイD2xィエD2. The electrical properties of this film were fine, namely high electric strength and low dielectric constant.
4) This result suggested that this film was applicable to interlayer insulation of integrated circuits and insulation of power apparatus.
5) The barrier discharge for application of VUV and decomposition of pollutants was analyzed by a computer simulation method.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), HOKKAIDO UNIVERSITY, 09555083 - Study on Optimization of Barrier Discharge Excimer-Lamp
Grants-in-Aid for Scientific Research
1995 - 1996
SAKAI Yosuke, IGARASHI Tatsusi, SUGAWARA Hirotake, VENTZEK Peter
In order to improve the capability of of Xe gas excimer lamps from which vacuum ultra-violet light is obtained, the characteristics and filamentation of barrier discharge plasma, and the factors which determine the light intensity and efficiency have been investigated. The main results obtained in this work are as follows.
1) In aXe gas barrier plasma, the magnitude of charge concentration accumulated on the surface of barriers increased with decreasing the frequencies of power source, and the production rate of excimers increased with decreasing the rise-time of the pulse voltage applied to plasma. Filamentation which might occur by non-uniformity in a uniform volume discharges was found to be initiated by a local gas temperature rise in excimer laser discharges.
2) In order to understand a relation between the laser spectroscopic signals and the plasma properties in non-equilibrium plasmas, the photon concentrations which are used for the laser diagnostics did not appreciably disturb the electron energy distribution but significantly changes the concentration of local excited levels.
3) In Xe/Ne mixtures, the laser absorption and opt-galvanic signals showed that the concentration of the metastable Xe was largest in the vicinity of the cathode under DC discharge. In the case of LF (10kHz-500kHz) discharges, the concentration had two peaks in the vicinity of the ground and powered electrodes.
As a conclusion it was suggested that an optimum design of excimer lamps was to utilize the sheath regions where the electron temperature was high enough to obtain a high value of excimer production rate.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), HOKKAIDO UNIVERSITY, 07558175 - 地球環境問題を考慮した高電圧電力機器絶縁に関する基礎的研究
科学研究費助成事業
1995 - 1995
田頭 博昭, 中神 芳武, 菅原 広剛, 下妻 光夫, 酒井 洋輔
本研究において、フロンを含有する絶縁材料の使用を排し、「地球にやさしい」新しい高電圧電力機器絶縁方式を確立するための基礎研究を行った。空気と微粉体の混合気体を用いた、フロンを含まない材料による気中ギャップの絶縁破壊電圧を、半球対半球ギャップ、あるいは球対球ギャップについて、実験的に研究した。直流、50Hz交流、標準雷インパルスの3種類の印加電圧波形について、データをとった。粉体材料としては、SiO_2、Si_3N_4、TiO_2、CeO_2、Al_2O_3、CuOを用い、粒径はそれぞれ10μmを平均として分布している。50Hz交流電圧印加時は、微粉体の効果は、ほぼここに記した順序でSiO_2が一番空気との比較において破壊電圧の上昇が大きい。2mmギャップにおいて、上昇率が最も大きく、約70%に達した。一方、Al_2O_3やCuOでは、上昇は極めてわずかであった。直流では一般に交流よりも上昇はわずかで、最も大きかったSiO_2でギャップ長3mmでも上昇率は15%程度であった。インパルス電圧印加の場合はパウダの量を準備する都合でCeO_2を除いた5種類について実験を行ったが、いずれの場合も20〜40%程度の破壊電圧の上昇が見られた。これらとは別に、直流および交流のみについCaCO_3パウダ、及びCa(OH)_2パウダに対しても実験を行った。比較的日常的に我々の周辺にある微粉体に興味がひかれたが、いずれも電圧上昇の効果は小さい上、Ca(OH)_2では破壊電圧は却って低下する結果が得られた。SiO_2パウダで典型的に現れるが、直流電圧印加時にパウダが電極(正電極)に付着する現象が見られる。これはパウダが電子を付着する機能を持つことを示し、破壊電圧の上昇を説明することができる。他の説明としては、パウダの電極への付着による電極の誘電体コーティングによる破壊電圧の上昇がある。現実にはこの両者が破壊電圧の上昇に同時に作用しているものと考えられる。
日本学術振興会, 一般研究(C), 北海道大学, 07650318 - プラズマプロセスによるフリーラジカル発生、反応、輸送と膜堆積過程の統合的研究
科学研究費助成事業
1994 - 1994
田頭 博昭, 横澤 亜由美, 菅原 広剛, ヴェンシェック ピーター, 酒井 洋輔
本研究は当初Si_3N_4薄膜を形成するためのラジカルを発生するRFプラズマのシミュレーション解析とその薄膜形成過程のシミュレーションに主としてあてられる予定であったが、Si_3N_4ならびにそのプリカーサラジカルに関する研究が不十分のため、急遽方針を転換して、次のような研究を行ない、成果を発表した。
1)アモルファスシリコン膜堆積についてダイヤモンド格子も用いたモデリングを行い、これによってスピン密度の研究を行なった。その結果、スピン密度を与えるもととなるダングリングボンドはボイド中にあるという結論を得たが、これはおそらく相当に堆積速度が大きく十分密な膜となっていないときの結果であろうと思われる。最近のきわめて良質な膜では、ボイドとダングリングボンドは相関が薄いと報告されており、この点の検討が、今後必要であることを明らかにした。
2)電荷転移と弾性衝突がある気体中のイオンの速度分布、スオームパラメータのモンテカルロ法による研究を行ない、電荷転移によるピークをもつ速度分布の特異な形状が弾性衝突により緩和されることを明らかにした。M.Kushnerが与えた周波数をもとにモノシランガス中のシリルイオンの拡散係数を求めた。
3)RF非平衡プラズマの制御を目的として、トランスジェント特性をもとめ、制御を行なうときの基礎的データを得た。また、比例オンオフ制御による制御性をシミュレーション研究し、制御可能性を見いだした。
4)来年度研究予定のTEOS中の電離係数を、北見工大吉田研究室と協力して測定し、初めてその値を与えた。これは、TEOSガス中のプラズマのシミュレーションの基礎を与えるものである。
日本学術振興会, 重点領域研究, 北海道大学, 06228203 - 高電圧電力機器絶縁に関する基礎的研究
科学研究費助成事業
1993 - 1994
田頭 博昭, ピーター ヴェンツェック, 菅原 広剛, 下妻 光夫, 酒井 洋輔
本研究はミクロンオーダーの直径を持つファインパウダを絶縁空間に浮遊させることにより気体の電気的絶縁破壊電圧を向上し、かつその種類を選ぶことにより、無公害的にこれを行ない、高電圧機器の電気的絶縁をハロゲンフリーな気体絶縁とする可能性を実験的に見いだすことを目的としている。以下に研究成果を報告する。
使用したパウダはSiO_2、TiO_2及びSi_3N_4で、電極間に印加した電圧は直流(DC)、50Hz交流(AC)及び標準雷インパルス(LI)である。LI印加時は、50%フラッシ-オーバ電圧V_<50>を昇降法により求めている。紫外線照射は行なっていない。
まず、SiO_2パウダで半球電極間にLIを印加した時、V_<50>はギャップ長1mmで空気の約1.6倍に上昇した。DC、AC電圧印加時にあったパウダの電極への付着はなかった。
TiO_2パウダではLI印加時で、SiO_2パウダ使用時とほぼ同程度で、ギャップ長1mmで空気での値の約1.5倍となった。しかし、DC及びAC電圧印加時では、絶縁破壊電圧の大幅な上昇はなかった。ACでは、約1.1〜1.2倍の上昇が見られたが、DCでは空気の絶縁破壊電圧とほぼ同じであった。いづれの電圧でも、SiO_2パウダの実験で見られたパウダの電極への付着は観察されなかった。
Si_3N_4パウダを用いて同様に実験を行なった。LI電圧印加時では、そのV_<50>はギャップ長1mmで空気の約1.6倍となった。AC及びDCでは、絶縁破壊電圧の大きな上昇は見られない。また、パウダの電極への付着も観察されていない。
LI電圧印加時では、いずれのパウダでも絶縁破壊電圧は空気より上昇した。しかし、AC及びDC電圧を印加した場合、SiO_2パウダを使用したときが最もパウダの効果が現れている。これは、パウダが帯電し電極に付着するということに関係しているものと思われる。各パウダでの、帯電の状況及び電極に付着した場合の付着量を調べ、絶縁破壊電圧の上昇の要因の検討を行なっている。
日本学術振興会, 一般研究(B), 北海道大学, 05452174 - コロナ放電による窒素酸化物公害ガス分解のシミュレーション
科学研究費助成事業
1993 - 1993
菅原 広剛
本研究は大気汚染の原因の1つとして考えられている窒素酸化物のコロナ放電による分解をコンピュータシミュレーションにより解析し、分解反応機構の解明ならびに分解反応の高効率化を図ることを目的とする。
コロナ放電のシミュレーションに必要な窒素酸化物分子の衝突断面積の推定は、定常タウンゼント法による電離係数の測定結果に、ボルツマン方程式解析による結果を合わせるよう断面積修正を繰返して行なう計画であったが、実際にボルツマン方程式解析を試みたところ、窒素酸化物のような電子付着性のガスの場合には計算が不安定となる場合があることがわかった。そこで、より安定な解析手法として、研究代表者らが開発しコロナ放電の解析に用いる計画であったプロパゲ-タ法を衝突断面積の推定にも導入することとした。
プロパゲ-タ法を定常タウンゼント法に適用する場合、従来の適用方法では電子の実空間における位置およびエネルギーの両方について空間分割を行なう必要があり、膨大な計算機容量を必要としていた。本研究ではこの点を踏まえ、エネルギーに関する空間分割のみで定常タウンゼント状態の解を求めることができる手法を新たに開発した。新手法の確立に伴って解析に必要な計算機容量が大幅に軽減されたため、従来は大型計算機で行なっていたシミュレーションが本年度購入備品の超高速アクセラレータボードをパーソナルコンピュータに搭載した計算機系で実行可能となった。
本研究で開発した手法は、解析に必要な計算機容量が従来の手法に比較して格段に小さい。また、本研究の対象である窒素酸化物のように、従来の手法では解析困難な場合があるとされている電子付着を含む条件にも対応可能な手法である。その成果は、研究発表覧に示すように英国物理学会誌に論文として掲載された。
日本学術振興会, 奨励研究(A), 北海道大学, 05750251 - プラズマプロセスによるフリーラジカル発生、反応、輸送と膜堆積過程の統合的研究
科学研究費助成事業
1993 - 1993
田頭 博昭, 横澤 亜由美, 菅原 広剛, 酒井 洋輔
1.平成5年度の研究目的は、モノシラン中の非平衡rfプラズマによる水素化アモルファスシリコン堆積時のラジカル発生、輸送、表面反応と膜堆積過程におけるラジカルの挙動を明らかにすることである。
2.平成5年度の研究成果は、以下の(1)〜(3)に要約される。(1)ラジカル発生のシミュレーション;比較的小規模な計算でラジカル発生量を求めることができる連続の式に基づくモデルをつくり、電極間のラジカル発生レート分布を求めた。モンテカルロモデルから得たラジカル発生レートとよい一致が得られた。(2)イオンの拡散係数と移動度の導出;上記のシミュレーション支援のため文献値がないモノシランイオンのドリフト速度および拡散係数、平均エネルギーをモンテカルロ法で求めた。衝突断面積は文献値を用いている。拡散係数は1Torr、E/N=1414Tdで約2500cm^2/sであった。(3)ラジカルによる膜堆積過程のシミュレーション;シリルラジカル等による膜堆積過程を解明するため、堆積サイトがダイヤモンド構造をなしているモデルを用いてモンテカルロ法で、堆積率、水素含有量、スピン密度、膜密度を求めた。従来用いていた立方格子モデルと比較して、膜密度および堆積率に関しては実験的に得られた値(2.1gcm^<-3>)あるいは傾向(基板温度にほとんど依存しない)とほぼ一致した。また水素含有量に関しては、基板温度200〜400°Cにおいて実験値と一致した値が得られたが、基板温度を500°C以上に加熱した場合、水素含有量がほぼ10%一定となり、実験値から得られる傾向より大きな値となった。これは隣接するH終端ボンドとダングリングボンドの結合に必要な活性化エネルギーを大きく見積りすぎたためと思われる。スピン密度に関しては、ラジカルとサイトの反応式の多くがダングリングボンドをつくり出すため、膜中にこれが残る可能性が高く、このため実験値とは大きく異なった値が得られたものと思われる。
日本学術振興会, 重点領域研究, 北海道大学, 05237203 - Fundamental Studies on LID Concentration and Discharge Decomposition of Nitrogen-Dioxide
Grants-in-Aid for Scientific Research
1992 - 1993
SAKAI Yosuke, SUGAWARA Hirotake, TABATA Masayoshi, TAGASHIRA Hiroaki
The ovjective of this work is to investigate a possibility of concentrating a very small amount of nitrogen-dioxide molecules in a flue gas and decomposing them by discharge and ultra-violet light. Light-induced-Drift(LID) technique is used for the comcentration. In this project the decomposition experiment and LID concentration experiment go side by side. The main results are as follows.
1)NO_2 molecules of 80%-90% were decomposed into N_2 and O_2 molecules in a NO_2 glow discharge with pressures between 1 and 7 Torr. It was shown that decomposed species, N_2 and O_<2'> were generated through NO.
2)In order to know the effect of ultre-violet light generated in the discharge on the NO_2 decomposition and a possibility of NO_2 decomposition by ultra-violent light, a trial of irradiation of UV light to NO_2 has been carried out. NO_2 was shown to be decomposed into N_2 and O_<2'> however the decomposing porcess was suggested to be different from the discharge process.
3) Values of the electron impace ionization coefficient and secondary coefficient for NO_2 gas are a few tens of percentage smaller than those for air, while the electron attachment coefficient for NO_2 is larger than that for O_2.
4)Using the results mentioned in 3) and the electron collision cross sections of N_2O which have been reported, the cross sections of NO_2 were estimated by Boltzman equation analysis method. These data play a very important role in analyzing the NO_2 decomposition process in discharges.
5)LID experiment system is now constructed, with a dye laser and a laser diode, and an improved type of drift tube. An experiment starts in SF_6 and He buffer gases.
The results mentioned above have been obtained, however investigation of NO_2 decomposition by UV light and its mechanism, detailed anallysis of scientific problem of LID concentration, development of NO_2 removal technology in a flue gas are not still finised. Further investifgation have to be carried on.
Japan Society for the Promotion of Science, Grant-in-Aid for General Scientific Research (B), Faculty of Engineering, Hokkaido University, 04452159 - 微粉体誘電体による気体(SF_6、空気)の絶縁耐力上昇機構に関する研究
科学研究費助成事業
1992 - 1992
田頭 博昭, 菅原 広剛, 下妻 光夫, 酒井 洋輔
本研究では、粒径の異なる4種類のSiO_2ファインパウダ(12μm、36μm50μm、150μm)ならびに異なる材質のパウダとしてSi_3N_4ファインパウダを空気中に浮遊させ、絶縁破壊電圧の測定を行いその諸特性について検訂した。また実験の際、質量の大きいパウダはファンによる浮遊が困難のため、電極間にパウダを散布する装置を作成し、2つの装置を用いて測定を行なった。結果を以下に示す。
(1) 12μmパウダを使用し、ファンを作動させた状態の交流絶縁破壊において、電極間にパウダのブリッジが形成されなくても絶縁破壊電圧は上昇した。この時、両電極に付着したパウダが電極間に流れこむのがみられ、これが絶縁破壊電圧の上昇に寄与しているものと思われる。 36μmパウダで同様の実験を行なったが、12μmパウダで確認されたほどの大きな絶縁破壊電圧の上昇はみられていない。
(2) 散布装置を用いた4種類の粒径の異なるSiO_2パウダに対する測定では、どの粒径のパウダも絶縁破壊電圧の大きな上昇は見られなかったが、粒径の大きいパウダと、小さいパウダではわずかであるが差があると思われる。また、同じ粒径でありながらファンによる結果(12μm、36μm)と差があるのは、電極付近にあるパウダの量の違いが影響しているものと考えられる。
(3) Si_3N_4パウダによる絶縁破壊実験ではパウダが重いため浮遊している量が少なく、絶縁破壊電圧の上昇はあまり見られない。散布の装置に替えて同様に測定を行なっても大きな上昇はみられていない。
(4) 直流での測定において、パウダが陽極側に多量に付着しており、パウダ自身は負に帯電しているものと考えられる。
日本学術振興会, 一般研究(C), 北海道大学, 04650227 - Modelling and Simulation of Weakly Ionized Plasmas
Competitive research funding