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土方 泰斗 ヒジカタ ヤスト

所属部署名 理工学研究科 数理電子情報部門 電話番号
職名 准教授 ■FAX番号
住所 埼玉県さいたま市桜区下大久保255 ■メールアドレス yasuto@opt.ees.saitama-u.ac.jp
■ホームページURL http://www.opt.ees.saitama-u.ac.jp/

プロフィール

兼担研究科・学部

工学部 電気電子システム工学科電子システム工学

研究分野

半導体結晶工学
半導体光物性

現在の研究課題

 炭化ケイ素半導体(SiC)を用いた超低損失MOSデバイスの開発を目指し、SiC/酸化膜界面の構造やSiCの酸化メカニズムを解明することを目的に研究を行っている。  酸化膜をnmオーダーの傾斜型に加工する独自の技術を開発した(業績7,8)。傾斜状酸化膜に対して分光エリプソメトリによる評価を行った結果、界面付近には厚さ1nm程の高屈折率界面層が存在し、その屈折率の値は酸化プロセスに依存することを明らかにした(業績7)。また、X線(放射光)光電子分光法によって界面付近における組成遷移層の存在と(業績6)、その層の厚さが界面準位密度の値と良く対応することを明らかにした(業績5)。  一方、酸化炉と分光エリプソメータを組み合わせたその場観察装置を開発し、SiCの酸化過程を実時間観察することを試みた(業績2,4)。その結果、酸化膜が20nm以下の酸化初期において、酸化速度が著しく増速することを初めて明らかにした(業績2,4)。また、このようなSiCの酸化の振る舞いを説明する「界面SiおよびC原子放出モデル」を提案し、本モデルが数nmから数100nmの広い膜厚領域で酸化速度データを良く再現することを示した(業績1)。  現在、面方位や酸化条件によるSiCの酸化速度の違いを統一的に説明する酸化モデルの構築と、本モデルを用いた界面層形成と界面準位発生のメカニズム解明を目指して研究を進めている。

所属学会

所属学会
応用物理学会

学歴

出身大学院・研究科等
1999 , 東京工業大学 , 博士 , 総合理工学研究科 , 物理情報工学専攻 , 修了
取得学位
博士(工学) , 東京工業大学 , 高周波音場計測のための小型光ファイバプローブに関する研究

受賞学術賞

2005 , 研究奨励賞 , 覚張光一(共著者:窪木亮一、土方泰斗、矢口裕之、吉田貞史)
2000 , 電気学会論文発表賞

研究職歴等

研究職歴
2006 , 埼玉大学大学院理工学研究科准教授
2005 - 2006 , イタリア国立研究所(CNR)客員研究員
1999 , 埼玉大学工学部助手

研究活動業績

研究業績(著書・発表論文等)

著書
"Investigation of SiC/Oxide Interface Structures by Spectroscopic Ellipsometry" (Chapter 4) in "Advanced Silicon Carbide Devices and Processing"
InTech:97-140 201509
ISBN:978-953-51-2168-8
Sadafumi Yoshida, Yasuto Hijikata and Hiroyuki Yaguchi

Physics and Technology of Silicon Carbide Devices
InTech 201301
Yasuto Hijikata

Nondestructive and Contactless Characterization Method for Spatial Mapping of the Thickness and Electrical Properties in Homo-Epitaxially Grown SiC Epilayers Using Infrared Reflectance Spectroscopy
InTech:3-26 201301
Sadafumi Yoshida, Yasuto Hijikata and Hiroyuki Yaguchi

Thermal Oxidation Mechanism of Silicon Carbide
InTech:181-206 201301
Yasuto Hijikata, Shuhei Yagi, Hiroyuki Yaguchi and Sadafumi Yoshida

SiC/GaNパワーデバイスの製造プロセスと放熱・冷却技術
技術情報協会:第1章第8節(14ペ-ジ) 201002

SiCパワーデバイス最新技術 =次世代パワーエレクトロニクス=
サイエンス&テクノロジー:23 2010

Properties and Applications of Silicon Carbide
INTECH open access publisher:12
Yasuto Hijikata, Hiroyuki Yaguchi, and Sadafumi Yoshida

論文
Radiation Response of Silicon Carbide Metal-Oxide-Semiconductor Transistors in High Dose Region
,Japanese Journal of Applied Physics,55:01AD01 2016
T. Ohshima, T. Yokoseki, K. Murata, T. Matsuda, S. Mitomo, H. Abe, T. Makino, S. Onoda, Y. Hijikata, Y. Tanaka, M. Kandori, S. Okubo, and T. Yoshie

Change in Characteristics of SiC MOSFETs by Gamma-ray Irradiation at High Temperature
,Materials Science Forum 2016
Takuma Matsuda, Takashi Tokoseki, Satoshi Mitomo, Koichi Murata, Takahiro Makino, Hiroshi Abe, Akinori Takeyama, Shinobu Onoda, Yuki Tanaka, Mikio Kandori, Toru Yoshie, Yasuto Hijikata, Takeshi Ohshima

Gamma-ray irradiation response of the motor-driver circuit with SiC MOSFETs
,Materials Science Forum 2016
Yugo Kobayashi, Takashi Yokoseki, Takuma Matsuda, Satoshi Mitomo, Koichi Murata, Michihiro Hachisuka, Yasuyoshi Kaneko, Takahiro Makino, Akinori Takeyama, Shinobu Onoda, Takeshi Ohshima, Yuki Tanaka, Mikio Kandori, Toru Yoshie, Yasuto Hijikata

Unified theory of silicon carbide oxidation based on the Si and C emission model
,Journal of Physics D: Applied Physics 2016
Daisuke Goto and Yasuto Hijikata

Effect of gamma-ray irradiation on the device process-induced defects in 4H-SiC epilayers
,Superlattices and Microstructures 2016
T. Miyazaki, T. Makino, A. Takeyama, S. Onoda, T. Ohshima, Y. Tanaka, M. Kandori, T. Yoshie, Y. Hijikata

Si and C emission into the oxide layer during the oxidation of silicon carbide and its influence on the oxidation rate
,AIP Advances,5:067128 2015
Yasuto Hijikata, Ryosuke Asafuji, Ryotaro Konno, Yurie Akasaka, Ryo Shinoda

Control of intermediate-band configuration in GaAs:N δ-doped superlattice
,Japanese Journal of Applied Physics,54:08KA04 2015
Kazuki Osada, Tomoya Suzuki, Shuhei Yagi, Shunya Naitoh, Yasushi Shoji, Yasuto Hijikata, Yoshitaka Okada, and Hiroyuki Yaguchi

Molecular beam epitaxial growth of intermediate-band materials based on GaAs:N δ-doped superlattices
,Japanese Journal of Applied Physics,54:08KA07 2015
Tomoya Suzuki, Kazuki Osada, Shuhei Yagi, Shunya Naitoh, Yasushi Shoji, Yasuto Hijikata, Yoshitaka Okada, and Hiroyuki Yaguchi

Photoluminescence study of oxidation-induced faults in 4H-SiC epilayers
,AIP Advances,5:127116 2015
Yutaro Miyano, Ryosuke Asafuji, Shuhei Yagi, Yasuto Hijikata, and Hiroyuki Yaguchi

Surface orientation dependence of SiC oxidation process studied by in-situ spectroscopic ellipsometry
,Materials Science Forum,821-823:371-374 2015
D. Goto, S. Yagi, Y. Hijikata, H. Yaguchi

Photoluminescence Study of Oxidation-Induced Stacking Faults in 4H-SiC Epilayers
,Materials Science Forum,821-823:327-330 2015
Y. Miyano, S. Yagi, Y. Hijikata, H. Yaguchi

Recovery of the Electrical Characteristics of SiC MOSFETs Irradiated with Gamma-rays by Thermal Treatments
,Materials Science Forum,821-823:705-708 2015
T. Yokoseki, H. Abe, T. Makino, S. Onoda, Y. Tanaka, M. Kandori, T. Yoshie, Y. Hijikata and T. Ohshima

Differences in SiC thermal oxidation process between crystalline surface orientations observed by in-situ spectroscopic ellipsometry
,Journal of Applied Physics,117:095306 2015
D. Goto, Y. Hijikata, S. Yagi, and H. Yaguchi

Growth temperature dependence of the surface segregation of Er atoms in GaAs during molecular beam epitaxy
,Japanese Journal of Applied Physics,54:051201 2015
R. G. Kim, S. Yagi, Y. Hijikata, and H. Yaguchi

Enhanced optical absorption due to E+-related band transition in GaAs:N delta-doped superlattices
,Applied Physics Express,7:102301 2014
Shuhei Yagi, Shunsuke Noguchi, Yasuto Hijikata, Shigeki Kuboya, Kentaro Onabe, Yoshitaka Okada, and Hiroyuki Yaguchi

Si emission into the oxide layer during oxidation of silicon carbide
,Materials Science Forum,778-780:553-556 2014
Y. Hijikata, Y. Akasaka, S. Yagi, and H. Yaguchi

Photoreflectance study of the temperature dependence of excitonic transitions in dilute GaAsN alloys
,Physica Status Solidi A,211:752-755 2014
W. Okubo, S. Yagi, Y. Hijikata, K. Onabe, and H. Yaguchi

Model calculations of SiC oxide growth rates at sub-atmospheric pressures using the Si and C emission model
,Materials Science Forum,Vols. 740-742:833-836 2013
Yasuto Hijikata, Shuhei Yagi, Hiroyuki Yaguchi, and Sadafumi Yoshida

Molecular beam epitaxy of ErGaAs alloys on GaAs (001)
, Journal of Crystal Growth,378:85-87 2013
R. G. Jin, S. Yagi, Y. Hijikata, S. Kuobya, K. Onabe, R. Katayama, H. Yaguchi

RF-MBE growth of cubic InN nano-scale dots on cubic GaN
,Journal of Crystal Growth,378:454-458 2013
J. Suzuki, M. Orihara, S. Yagi, Y. Hijikata, H. Yaguchi

Analysis of Electronic Structures of Nitrogen Delta-Doped GaAs Superlattices for High Efficiency Intermediate Band Solar Cells
, IEEE J. PHOTOVOLTAICS,3:1287-1291 2013
S. Noguchi, S. Yagi, D. Sato, Y. Hijikata, K. Onabe, S. Kuboya, and H. Yaguchi

Conversion Efficiency of Intermediate Band Solar Cells with GaAs:N Delta-Doped Superlattices
, Japanese Journal of Applied Physics,52:102302 2013
S. Yagi, S. Noguchi, Y. Hijikata, S. Kuboya, K. Onabe, and H. Yaguchi

Stacked structure of self-organized cubic InN nano-dots grown by molecular beam epitaxy
,Physica Status Solidi C,10:1545-1548 2013
S. Yagi, J. Suzuki, M. Orihara, Y. Hijikata, and H. Yaguchi

Biexciton emission from single isoelectronic traps formed by nitrogen-nitrogen pairs in GaAs
,AIP Conference Prodeedings,1566:538-539 2013
K. Takamiya, T. Fukushima, S. Yagi, Y. Hijikata, T. Mochizuki, M. Yoshita, H. Akiyama, S. Kuboya, K. Onabe, R. Katayama and H. Yaguchi

Single Photon Generation from Nitrogen Atomic-Layer Doped Gallium Arsenide
,Mater. Sci. Forum,706-709:2916-2921 2012
Kengo Takamiya, Yuta Endo, Toshiyuki Fukushima, Shuhei Yagi, Yasuto Hijikata, Toshimitsu Mochizuki, Masahiro Yoshita, Hidefumi Akiyama, Shigeyuki Kuboya, Kentaro Onabe, Ryuji Katayama and Hiroyuki Yaguchi

RF-MBE growth of semipolar InN(10-13) and InGaN(10-13) on GaAs(110)
,Phys. Status Solidi C,9:658-661 2012
Misao Orihara, Shuhei Yagi, Yasuto Hijikata, and Hiroyuki Yaguchi

Micro-Photoluminescence study on the influence of oxidation on stacking faults in 4H-SiC epilayers
,Applied Physics Express,vol. 5:a.n. 051302 2012
Hikaru Yamagata, Shuhei Yagi, Yasuto Hijikata, and Hiroyuki Yaguchi

Oxygen partial pressure dependence of the SiC oxidation process studied by in-situ spectroscopic ellipsometry
,Journal of Applied Physics,Vol. 112:a.n. 024502 2012
Keiko Kouda, Yasuto Hijikata, Shuhei Yagi, and Hiroyuki Yaguchi

Biexciton Luminescence from Individual Isoelectronic Traps in Nitrogen δ-Doped GaAs
,Applied Physics Express,Vol. 5:a.n. 111201 2012
Kengo Takamiya, Toshiyuki Fukushima, Shuhei Yagi, Yasuto Hijikata, Toshimitsu Mochizuki, Masahiro Yoshita, Hidefumi Akiyama, Shigeyuki Kuboya, Kentaro Onabe, Ryuji Katayama, and Hiroyuki Yaguchi

Theoretical studies for Si and C emission into SiC layer during oxidation
,Mater. Sci. Forum,679-680:429-432 2011
Yasuto Hijikata, Hiroyuki Yaguchi, and Sadafumi Yoshida

In-situ Spectroscopic Ellipsometry Study of SiC Oxidation at Low Oxygen-Partial-Pressures
,Materials Science Forum,645-648:813-809 2010
Keiko Kouda, Yasuto Hijikata, Hiroyuki Yaguchi and Sadafumi Yoshida

Model calculations of SiC oxide growth rate at various oxidation temperatures based on the silicon and carbon emission model
,Materials Science Forum,645-648:809-812 2010
Yasuto Hijikata, Hiroyuki Yaguchi and Sadafumi Yoshida

Photoluminescence from single isoelectronic traps in nitrogen delta-doped GaAs grown on GaAs(111)
,Physica E,42:2529-2531 2010
T. Fukushima, Y. Hijikata, H. Yaguchi, S. Yoshida, M. Okano, M. Yoshita, H. Akiyama, S. Kuboya, R. Katayama, K. Onabe

RF-MBE growth of InN on 4H-SiC (0001) with off-angles
,Physica Satatus Solidi C,7:2016-2018 2010
Misao Orihara, Shin Takizawa, Takanori Sato, Yuuki Ishida, Sadafumi Yoshida, Yasuto Hijikata, and Hiroyuki Yaguchi

SiC半導体の酸化メカニズム解明に関する研究
,平成21年度総合研究機構プロジェクト研究成果報告書,8:63 2010
土方泰斗

Optical and Electrical Characterizations of 4H-SiC-Oxide interfaces by Spectroscopic Ellipsometry and Capacitance-Voltage measurements
,Applied Surface Science,255:8648-8653 2009
Hideki Hashimoto, Yasuto Hijikata, Hiroyuki Yaguchi and Sadafumi Yoshida

A Kinetic Model of Silicon Carbide Oxidation Based on the Interfacial Silicon and Carbon Emission Phenomenon
,Applied Physics Express,2:021203 2009
Yasuto Hijikata, Hiroyuki Yaguchi, and Sadafumi Yoshida

Characterization of 4H-SiC-SiO2 Interfaces by a Deep Ultraviolet Spectroscopic Ellipsometer
,Materials Science Forum,615-617:505-508 2009
Hideyasu Seki, Takahiro Wakabayashi, Yasuto Hijikata, Hiroyuki Yaguchi and Sadafumi Yoshida

Model Calculation of SiC Oxidation Rates in the Thin Oxide Regime
,Materials Science Forum,600-603:663-666 2009
Yasuto Hijikata, Takeshi Yamamoto, Hiroyuki Yaguchi and Sadafumi Yoshida

Model Calculation of SiC Oxide Growth Rate based on the Silicon and Carbon Emission Model
,Materials Science Forum,615-617:489-492 2009
Yasuto Hijikata, Hiroyuki Yaguchi and Sadafumi Yoshida

Observation of SiC Oxidation in Ultra-Thin Oxide Regime by In-Situ Spectroscopic Ellipsometry
,Materials Science Forum,615-617:509-512 2009
Toshiyuki Takaku, Yasuto Hijikata, Hiroyuki Yaguchi and Sadafumi Yoshida

Oxygen-Partial-Pressure Dependence of SiC Oxidation Rate Studied by In-situ Spectroscopic Ellipsometry
,Materials Science Forum,600-603:667-670 2009
Takeshi Yamamoto, Yasuto Hijikata, Hiroyuki Yaguchi and Sadafumi Yoshida

Oxide Growth Rate Enhancement of Silicon Carbide (0001) Si-Faces in Thin Oxide Regime
,Japanese Journal of Applied Physics,47(10):7803-7806 200810
Takeshi Yamamoto;Yasuto Hijikata;Hiroyuki Yaguchi;Sadafumi Yoshida

Twin photoluminescence peaks from single isoelectronic traps in nitrogen delta-doped GaAs
,Physica E-Low-Dimensional Systems & Nanostructures,40(6):2110-2112 200804
Y. Endo;Y. Hijikata;H. Yaguchi;S. Yoshida;M. Yoshita;H. Akiyama;F. Nakajima;R. Katayama;K. Onabe

等電子トラップを利用した単一光子発生素子の作製
,科学研究費補助金(基盤研究(c))研究成果報告書,平成17-18年度 200703
矢口裕之,吉田貞史,土方泰斗

Growth Rate Enhancement of (000 -1)-Face Silicon-carbide Oxidation in Thin Oxide Regime
,Japanese Journal of Applied Physics,46:L770-L772 2007
Takeshi Yamamoto, Yasuto Hijikata, Hiroyuki Yaguchi, and Sadafumi Yoshida

MOS capacitors obtained by wet oxidation of n-type 4H-SiC pre-implanted with Nitrogen
,Microelectronic Engineering,84:2804-2809 2007
A. Poggi, F. Moscatelli, Y. Hijikata, S. Solmi and R. Nipoti

酸化膜/炭化珪素半導体界面の窒素による界面順位密度低減のメカニズム解明
埼玉大学総合研究機構,総合研究機構研究プロジェクト研究成果報告書,第5号(18年度):592-593 2007
土方泰斗
A study on reduction mechanism of interface state density using nitridation of oxide/SiC semiconductor interface

Characterization of Oxide Films on 4H-SiC Epitaxial (000-1) Faces by High-Energy-Resolution Photoemission Spectroscopy: Comparison between Wet and Dry Oxidation
,Journal of Applied Physics,100:053710 2006
Y. Hijikata, H. Yaguchi, S. Yoshida, Y. Takata, K. Kobayashi, H. Nohira, and T. Hattori

Simultaneous Determination of Carrier Concentration, Mobility and Thickness of SiC Homo-Epilayers Using Infrared Reflectance Spectroscopy
,Japanese Journal of Applied Physics,45:L1226-L1229 2006
Shingo Oishi, Yasuto Hijikata, Hiroyuki Yaguchi, and Sadafumi Yoshida

Effect of Ar Post-Oxidation Annealing on Oxide-4H-SiC Interfaces Studied by Capacitance to Voltage Measurements and Photoemission Spectroscopy
,Journal of Vacuum Science Technology A,23(2):298-303 2005
Hijikata Y., Yaguchi H., Ishida Y., Yoshikawa M., and Yoshida S.

Characterization of Carrier Concentration and Mobility in n-type SiC Wafers Using Infrared Reflectance Spectroscopy
,Japanese Journal of Applied Physics,43:5151 -5156 2004
Narita K., Hijikata Y., Yaguchi H., Yoshida S., and Nakajima S.

ファブリペロー型光ファイバ超音波プローブの受音特性 (<特集>光-超音波エレクトロニクス論文特集)
電子情報通信学会,電子情報通信学会論文誌. C, エレクトロニクス,J86-C(12):1340-1341 200312
中村健太郎,土方泰斗
Receiving Characteristicb of a Fabry-Perot Cavity Fiber Optir Ultrasonic Probe

Electrical Characteristics of Interface Defects in Oxides Grown at 1200℃ in Dry Oxygen Ambient on Silicon Carbide and Their
電子情報通信学会,IEICE transactions on electronics,E86-C(4):688-688 200304
土方泰斗

炭化ケイ素基板上に成長させた1200℃ドライ酸化膜中の界面欠陥の電気特性とその熱アニーリング効果 (<特集>ワイドギャップ半導体とその電子デバイス応用論文小特集)
電子情報通信学会,電子情報通信学会論文誌. C, エレクトロニクス,J86-C(4):426-433 200304
土方泰斗,吉田貞史,吉川正人,石田夕起,直本保,伊藤久義,奥村元,高橋徹夫,土田秀一

Measurement of the depth profile of the refractive indices in the oxide films on SiC by spectroscopic ellipsometry
,Japanese Journal of Applied Physics,41:800-804 2002
T. Iida, Y. Tomioka, K. Yoshimoto, M. Midorikawa, H. Tukada, Y. Hijikata, M. Orihara, H. Yaguchi, M. Yoshikawa, Y. Ishida, and S. Yoshida

Composition Analysis of SiO2/SiC Interfaces by Electron Spectroscopic Measurements using Slope Shaped Oxide Films
,Applied Surface Science,184:161-166 2001
Y. Hijikata, H. Yaguchi, M. Yoshikawa and S. Yoshida

Wavelength-Division-Multiplexing in Fiber-Optic Micro-Probe Array for Ultrasonic Field Measurements (Special Issue on Optical Fiber Sensors)
電子情報通信学会,IEICE transactions on electronics,E83-C(3):293-297 200003
土方泰斗,中村健太郎

学会発表
Model calculations of SiC oxide growth rates at sub-atmospheric pressures using the Si and C emission model
9th European Conference on SiC and Related Matterials,ECSCRM2012, Saint-Petersburg, Russia,TuP-63 201209
Y. Hijikata, S. Yagi, H. Yaguchi, and S. Yoshida

Theoretical studies for Si and C emission into SiC layer during oxidation
8th European Conference on Silicon Carbide and Related Materials,ECSCRM2010, Oslo, Norway,Mo3-6:93 201008
Yasuto Hijikata, Hiroyuki Yaguchi, and Sadafumi Yoshida