Updated on 2024/07/27

写真a

 
Naotaka Iwata
 
Organization
Specially Appointed Faculty Specially Appointed Professor Iwata Laboratory Specially Appointed Professor   
Degree
博士（工学） （ 1999.3   筑波大学 ）
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Contact information
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Research Areas

  • Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Electron device and electronic equipment  / GaN, Power device, Semiconductor processing

Main research papers

  • Breakdown voltage enhancement of p-GaN/AlGaN/GaN diode by controlling Mg acceptors for compensating residual Si donors

    S. Kawata, Y. Zhang, and N. Iwata

    Jpn. J. of Appl.Phys.   62 ( SA1004 )   2022.11.11

    Low turn-on voltage rectifier using p-GaN gate AlGaN/GaN high electron mobility transistor for energy harvesting applications

    Y. Zhang, S. Kawata, and N. Iwata

    Jpn. J. of Appl. Phys.   61 ( SA1013 )   2021.12.15

    Effect of C- and Fe-doped GaN buffer on AlGaN/GaN high electron mobility transistor performance on GaN substrate using side-gate modulation

    M. E. Villamin, T. Kondo, and N. Iwata

    Jpn. J. Appl. Phys.   60 ( SBBD17 )   2021.3.16

    High-selectivity dry etching for p-type GaN gate formation of normally-off operation high-electron-mobility transistor

    N. Iwata and T. Kondo

    Jpn. J. of Appl. Phys.   60 ( SAAD01 )   2020.10.16

    Laser-induced local activation of Mg-doped GaN with a high lateral resolution for high power vertical devices

    N. Kurose, K. Matsumoto, F. Yamada, T. M. Roffi, I. Kamiya, N. Iwata, and Y. Aoyagi

    AIP Advances   8 ( 015329 )   2018.1.31

Research History

  • Ritsumeikan University

    2015.5 - 2016.3

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    Country：Japan

  • Toyota Technological Institute   Professor

    2013.4

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    Country：Japan

  • The University of Electro-Communications   Cooperative Research Center

    2005.4 - 2011.3

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    Country：Japan

  • Stanford大学   J.S.Harris教授研究室   客員研究員

    1993.1 - 1993.12

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    Country：United States

  • NEC、NECエレクトロニクス、ルネサス エレクトロニクス株式会社   基礎研究所、マイクロエレクトロニクス研究所、関西エレクトロニクス研究所、化合物デバイス事業部

    1983.4 - 2013.3

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    Country：Japan

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Education

  • University of Tsukuba

    1999.3

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    Country： Japan

  • University of Tsukuba   Master's Program in Science and Engineering

    1981.4 - 1983.3

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    Country： Japan

  • The University of Electro-Communications   Faculty of Electro-Communications

    1977.4 - 1981.3

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    Country： Japan

Professional Memberships

  • 応用物理学会

    2013.8

  • 電子情報通信学会

    1995.2

  • The Institute of Electrical and Electronics Engineers

    1993.12

Committee Memberships

  • International Conference on Solid State Devices and Materials (SSDM)   Program committee member  

    2021.11   

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    Committee type：Academic society

  • International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials (ISPlasma)   Program committee member  

    2018.4   

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    Committee type：Academic society

Research theme

  • Research on compound semiconductor heterojunction power devices

    岩田　直高, VILLAMIN　Maria　Emma　

    2017

  • Research on ultra-low power consumption semiconductor devices and systems

    岩田　直高, VILLAMIN　Maria　Emma　

    2017

  • Passivation-capping of III-V semiconductor quantum structures by oxides

    神谷　格, Ronel　Christian　Intal　ROCA, 岩田　直高

    2017

Papers

  • Passivation capping of InAs surface quantum dots by TMA/Al2O3: PL enhancement and blueshift suppression Reviewed

    Hanif Mohammadi, Ronel C. Roca, Yuwei Zhang, Hyunju Lee, Yoshio Ohshita, Naotaka Iwata, Itaru Kamiya

    Journal of Applied Physics   133   185303 - 185303   2023.5

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    Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Americal Institute of Physics  

    DOI： doi.org/10.1063/5.0140035

  • Breakdown voltage enhancement of p-GaN/AlGaN/GaN diode by controlling Mg acceptors for compensating residual Si donors Reviewed

    Soichiro Kawata*, Yuwei Zhang*, Naotaka Iwata

    Japanese Journal of Applied Physics   62   SA1004 - 1   2022.11

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    Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)  

  • ArF excimer laser activation of Mg-doped GaN small area mesa device Reviewed International coauthorship

    M.E. Villamin, R.C. Roca, I. Kamiya, N. Iwata

    Proc. SPIE Gallium Nitride Materials and Devices XIX   12886   128860F   2024.3

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    Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：SPIE  

    DOI： 10.1117/12.3002082

  • Atomic layer deposition of diethylzinc/zinc oxide on InAs surface quantum dots: Self-clean-up and passivation processes Reviewed

    Hanif Mohammadi*, Ronel Christian Intal ROCA, Yuwei Zhang*, Hyunju Lee*, Yoshio Ohshita, Naotaka Iwata, Itaru Kamiya

    Applied Surface Science   612   155790   2022.11

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    Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

  • Low turn-on voltage rectifier using p-GaN gate AlGaN/GaN high electron mobility transistor for energy harvesting applications Reviewed

    ジャン　ユーウェイ, Soichiro Kawata*, Naotaka Iwata

    Japanese Journal of Applied Physics   61   SA1013 - 1   2021.12

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    Authorship：Last author   Publishing type：Research paper (scientific journal)  

  • Characterization of AlGaN/GaN high electron mobility transistors on GaN substrates with different thicknesses of GaN channel and buffer layers using side-gate modulation Reviewed

    VILLAMIN, Maria Emma C., Naotaka Iwata

    Japanese Journal of Applied Physics   61   SA1015 - 1   2021.12

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    Authorship：Last author   Publishing type：Research paper (scientific journal)  

  • High breakdown voltage of AlGaAs/GaAs/AlGaAs diode achieved by balanced charges considering residual carbon impurity in hole and electron channels Reviewed

    Hiroaki Ogawa*, Soichiro Kawata*, Naotaka Iwata

    Japanese Journal of Applied Physics   60   041001 - 1   2021.4

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    Authorship：Last author   Publishing type：Research paper (scientific journal)  

  • Effect of C- and Fe-doped GaN buffer on AlGaN/GaN HEMT performance on GaN substrate using side-gate modulation Reviewed

    VILLAMIN, Maria Emma C., Takaaki Kondo*, Naotaka Iwata

    Japanese Journal of Applied Physics   60   SBBD17 - 1   2021.3

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    Authorship：Last author   Publishing type：Research paper (scientific journal)  

  • High-selectivity dry etching for p-type GaN gate formation of normally-off operation high-electron-mobility transistor Reviewed

    Naotaka Iwata, Takaaki Kondo*

    Japanese Journal of Applied Physics   60   SAAD01 - 1   2020.10

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    Authorship：Lead author   Publishing type：Research paper (scientific journal)  

  • High-selectivity dry etching for p-type GaN gate formation of normally-off operation high-electron-mobility transistor Reviewed

    Naotaka Iwata, Takaaki Kondo*

    Japanese Journal of Applied Physics   60   SAAD01 - 1   2020.10

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    Authorship：Lead author   Publishing type：Research paper (scientific journal)  

  • Effects of p-GaN gate structures and fabrication process on performances of normally-off AlGaN/GaN high electron mobility transistors Reviewed

    Takaaki Kondo*, Yoshihiko Akazawa*, Naotaka Iwata

    Japanese Journal of Applied Physics   59   SAAD02 - 1   2019.11

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    Authorship：Last author   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Applied Physics  

  • Carrier Transportation at Novel Silver Paste Contact Reviewed

    神岡　武文, Satoshi Kameyama, Kazuo Muramatsu, Aki Tanaka*, Naotaka Iwata, Kyotaro Nakamura, Atsushi Ogura*, Yoshio Ohshita

    Proceedings of the 44th IEEE Photovoltaic Specialists Conference (PVSC44)   2018.3

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    Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

  • Laser-induced local activation of Mg-doped GaN with a high lateral resolution for high power vertical devices Reviewed

    Noriko Kurose **, Kota Matsumoto*, 山田　郁彦, テウク モハマド ロフィ, Itaru Kamiya, Naotaka Iwata, Yoshinobu Aoyagi **

    AIP Advances   8 ( 015329 )   1 - 5   2018.1 （   ISSN:2158-3226 ）

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    Publishing type：Research paper (scientific journal)   Publisher：American Institute of Physics  

  • Charge-Controllable Mg-Doped AlOx Passivation Layers for p- and n-Type Silicon Reviewed

    リ　ヒュンジュ, Fumiya Nishimura*, Haruhiko Yoshida*, 神岡　武文, Naotaka Iwata, Yoshio Ohshita

    Proceedings of the 33rd European Photovoltaic Solar Energy Conference and Exhibition   399 - 401   2017.11 （ ISBN:3-936338-47-7 ）

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    Publishing type：Research paper (international conference proceedings)   Publisher：WIP  

  • Excellent Surface Passivation of Crystalline Silicon by Ternary AlxMg1-xOy Thin Films Reviewed

    リ　ヒュンジュ, 神岡　武文, Dongyan Zhang*, Naotaka Iwata, Yoshio Ohshita

    Proceedings of the 43th IEEE Photovoltaic Specialists Conference (PVSC43)   2931 - 2934   2016.11 （ ISBN:978-1-5090-2724-8 ）

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    Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

  • Realization of Conductive AlN Epitaxial Layer on Si Substrate using Spontaneously Formed Nano-Size Via-Holes for Vertical AlGaN High Power FET Reviewed

    Noriko Kurose **, Kota Ozeki **, Tsutomu Araki **, Naotaka Iwata, Itaru Kamiya, Yoshinobu Aoyagi **

    The 43rd International Symposium on Compound Semiconductors (ISCS), Toyama Japan   ThD2 - 4   2016.6

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    Publishing type：Research paper (international conference proceedings)   Publisher：The Japan Society of Applied Physics and The Institute of Electrical and Electronic Engineers  

  • SiNx Passivated GaN HEMT by Plasma Enhanced Atomic Layer Deposition Reviewed

    Takayuki Suzuki*, Tomiaki Yamada*, Ryosuke Kawai*, Shohei Kawaguchi*, Dongyan Zhang*, Naotaka Iwata

    The 43rd International Symposium on Compound Semiconductors (ISCS), Toyama Japan   MoP - ISCS   2016.6

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    Authorship：Last author   Publishing type：Research paper (international conference proceedings)  

  • InGaAs triangular barrier photodiodes for high-responsivity detection of near-infrared light Reviewed

    Kazuya Sugimura*, Masato Ohmori*, Takeshi Noda **, Tomoya Kojima*, Sakunari Kado*, Pavel Vitushinskiy*, Naotaka Iwata, Hiroyuki Sakaki*

    Applied Physics Express   9   062101   2016.5

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    Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Applied Physics  

  • The Current Conduction Mechanism of Novel Silver Thick Film Electrode Reviewed

    Tetsu Takahashi*, Tomihisa Tachibana*, 神岡　武文, Naotaka Iwata, Yoshio Ohshita

    Proc. 31st European Photovoltaic Solar Energy Conference and Exhibition   696 - 699   2015.11

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    Publishing type：Research paper (international conference proceedings)   Publisher：WIP  

  • AlGaAs/InGaAs HEMTs Passivated with Atomic Layer Deposited SiO2 using Aminosilane Precursors Reviewed

    Takayuki Suzuki 電子デバイス*, Yousuke Takigawa 電子デバイス*, Naotaka Iwata, チョウ　トウエン, Yoshio Ohshita

    2015 IEEE International Meeting for Future of Electron Devices, Kansai (IMFEDK)   2015.6

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    Publishing type：Research paper (scientific journal)   Publisher：IEEE  

    DOI： 10.1109/IMFEDK.2015.7158492

  • Formation of conductive spontaneous via holes in AlN buffer layer on n+Si substrate by filling the vias with n-AlGaN by metal organic chemical vapor deposition and application to vertical deep ultraviolet photo-sensor Reviewed

    Noriko Kurose Ritsumeikan University*, Naotaka Iwata, Itaru Kamiya, Yoshinobu Aoyagi Ritsumeikan University*

    AIP Advances   4   123007   2014.12

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    Publishing type：Research paper (scientific journal)   Publisher：The American Institute of Physics  

  • Si etching with reactive neutral beams of very low energy Reviewed

    Yasuhiro Hara Kansai Unversity*, Takaya Mise RIKEN*, Manabu Hamagaki RIKEN*, Naotaka Iwata, 原　民夫

    Journal of Applied Physics   116 ( 22 )   223301   2014.12

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    Publishing type：Research paper (scientific journal)   Publisher：The American Institute of Physics  

  • Evaluation of Interface Recombination Induced by Fire-through Ag Past for High Open Circuit Voltage Reviewed

    M. Aoki*, Yoshio Ohshita, T. Takahashi*, 立花　福久, I. Suminta, Y. Takigawa*, Naotaka Iwata

    Proc. 29th European Photovoltaic Solar Energy Conference and Exhibition   1368 - 1370   2014.11

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    Authorship：Last author   Publishing type：Research paper (international conference proceedings)   Publisher：WIP  

  • 1.8V Operation Power Amplifier IC for Bluetooth Class 1 Utilizing p^+-GaAs Gate Hetero-Junction FET Reviewed

    HARIMA Fumio, BITO Yasunori, TAKAHASHI Hidemasa, IWATA Naotaka

    IEICE Trans. Electron.   91 ( 7 )   1104 - 1108   2008.7 （   ISSN:0916-8524 ）

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    Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Institute of Electronics, Information and Communication Engineers  

    We have developed a power amplifier IC for Bluetooth Class 1 operating at single low voltage of 1.8V for both control and drain voltages. We can realize it due to fully enhancement-mode hetero-junction FETs utilizing a re-grown p+-GaAs gate technology. The power amplifier is a highly compact design as a small package of 1.5mm×1.5mm×0.4mm with fully integrated gain control and shutdown functions. An impressive power added efficiency of 52% at an output power of 20dBm is achieved with an associated gain of 22dB. Also, sufficiently low leakage current of 0.25μA at 27°C is exhibited, which is comparable to conventional HBT power amplifiers.

    DOI： 10.1093/ietele/e91-c.7.1104

  • SrTiO 3 Capacitor with Relative Dielectric Constant of 200 on GaAs Substrate at Microwave Frequency Reviewed

    Nishimura Takeshi, Iwata Naotaka, Takemura Koichi, Kuzuhara Masaaki, Miyasaka Yoichi

    Jpn J Appl Phys   35 ( 12 )   L1683 - L1684   1996.12 （   ISSN:0021-4922 ）

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    Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Applied Physics  

    An RF-sputtered SrTiO3 (STO) capacitor was fabricated on a GaAs substrate. Microwave characterization exhibited a relative dielectric constant (εr) of 200 up to 20 GHz. This high ε r was obtained when the base electrode and the STO film were sputter-deposited in succession. A novel Pt/Ti/Pt/Ti base metal exhibited high tolerance against ion-milling, resulting in lower Ohmic resistance compared to the conventional base metal, Pt/Ti.

    DOI： 10.1143/JJAP.35.L1683

    Other Link： https://jlc.jst.go.jp/DN/JALC/00044138165?from=CiNii

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MISC

  • 携帯電話アンテナインピーダンス整合用GaAsスイッチIC (電子デバイス特集) -- (モバイル、ワイヤレス分野に向けた半導体・ソリューション)

    岩田 直高, 藤田 祐智

    NEC技報   62 ( 1 )   34 - 37   2009.1 （   ISSN:0285-4139 ）

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    Language：Japanese   Publisher：日本電気  

  • ワイヤレスブロードバンド用GaAsスイッチIC (電子デバイス特集) -- (デジタルコンシューマ分野向け半導体)

    岩田 直高, 椙田 耕太郎

    NEC技報   60 ( 4 )   22 - 25   2007.10 （   ISSN:0285-4139 ）

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    Language：Japanese   Publisher：日本電気  

  • High Power GaAs Heterojunction FET with Dual Field-Modulating-Plates for 28V Operated W-CDMA Base Station

    ISHIKURA Kouji, TAKENAKA Isao, TAKAHASHI Hidemasa, HASEGAWA Kouichi, ASANO Kazunori, IWATA Naotaka

    IEICE transactions on electronics   90 ( 5 )   923 - 928   2007.5 （   ISSN:0916-8524 ）

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    Language：English   Publisher：The Institute of Electronics, Information and Communication Engineers  

    This report presents Dual Field-modulating-Plates (Dual-FP) technology for a 28V operated high power GaAs heterojunction FET (HJFET) amplifier. A developed HJFET has two FP electrodes; the 1st-FP is connected to the gate and the 2nd-FP to the ground. The 2nd-FP suppresses the drain current dispersion effectively cooperating with the 1st-FP, and it can also reduce the gate-drain parasitic capacitance. The developed push-pull amplifier, with four Dual-FPFET chips, demonstrated 55.1dBm (320W) output power with a 14.0dB linear gain and a drain efficiency of 62% at 2.14GHz. Under two-carrier W-CDMA signals, it showed a high drain efficiency of 30% and low third-order Inter-modulation distortion of -37dBc at output power of 47.5dBm.

  • A Distortion-Cancelled Doherty 28V Operated 330W GaAs Heterojunction FET Power Amplifier for Cellular Base Stations

    TAKENAKA Isao, ISHIKURA Kohji, TAKAHASHI Hidemasa, HASEGAWA Kouichi, UEDA Takashi, KURIHARA Toshimichi, ASANO Kazunori, IWATA Naotaka

    IEICE technical report   106 ( 459 )   149 - 154   2007.1 （   ISSN:0913-5685 ）

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    Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

    A low distortion Doherty high-power amplifier has been developed for cellular base stations. The amplifier delivered 330W-saturated output-power at 2.14GHz with a pair of 28V operated 150W GaAs heterojunction field-effect-transistors. Utilizing the distortion cancellation effect between the main and the peak amplifiers in Doherty configuration, it demonstrated low third order intermodulation of -37dBc with a high drain efficiency of 42% at an output power of 49dBm around 6dB back-off level under the two-carrier wideband code division multiple access (W-CDMA) signals of 2.135GHz and 2.145GHz. In addition, we proposed the evaluation techniques to obtain each AM-AM and AM-PM characteristics of the main and the peak amplifiers in an operating Doherty amplifier, and experimentally proved the distortion cancellation effect in the GaAs FET Doherty amplifier.

  • CT-1-7 Application of GaAs Heterojunction FETs to Power Amplifiers and Switches

    Iwata Naotaka

    Proceedings of the IEICE General Conference   2006 ( 2 )   "SS - 11"   2006.3

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    Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

  • SC-7-2 Linearization of Class AB Amplifiers Based on Predistortion for High Efficiency, Low Distortion Operation

    Hau Gary, Nishimura B. Takeshi, Takahashi Hidemasa, Iwata Naotaka

    Proceedings of the IEICE General Conference   2001 ( 2 )   179 - 180   2001.3

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    Language：English   Publisher：The Institute of Electronics, Information and Communication Engineers  

  • High Efficiency 240W Power Heterojunction FETs for W-CDMA Base Stations

    ISHIKURA K., TAKENAKA I., KISHI K., OGASAWARA Y., HASEGAWA K., EMORI F., IWATA N.

    Proceedings of the IEICE General Conference   2001 ( 2 )   67 - 67   2001.3

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    Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

  • 1.0V Operation Power Heterojunction FET for Digital Cellular Phones

    KATO Takehiko, BITO Yasunori, IWATA Naotaka

    IEICE Trans. Electron.   84 ( 2 )   249 - 252   2001.2 （   ISSN:0916-8524 ）

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    Language：English   Publisher：The Institute of Electronics, Information and Communication Engineers  

    This paper describes 1.0V operation power performance of a double doped AIGaAs/InGaAs/AIGaAs heterojunction FET for personal digital cellular phones. The developed FET with a multilayer cap consisting of a highly Si-doped GaAs, an undoped GaAs and a highly Si-doped AIGaAs exhibited an on-resistance of 1.3Ω・mm and a maximum drain current of 620mA/mm. A 28mm gate-width device, operating with a drain bias voltage of 1.0V, demonstrated an output power of 1.0W, a power-added efficiency of 59% and an associated gain of 13.7dB at an adjacent channel leakage power at 50kHz offcenter frequency of -48dBc with a 950MHz π/4-shifted quadrature phase shift keying signal.

  • High Efficiency Power Amplifier Module with Novel Enhancement-Mode Heterojunction FETs for Wide-Band CDMA Handsets

    BITO Yasunori, KATO Takehiko, KATO Teruhisa, IWATA Naotaka

    IEICE technical report. Microwaves   100 ( 551 )   23 - 28   2001.1 （   ISSN:0913-5685 ）

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    Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

    A 0.1cc highly efficient power amplifier multi chip module(MCM) employing novel enhancement-mode double-doped AlGaAs/InGaAs/AlGaAs heterojunction FETs(HJFET) has been successfully developed for 1.9GHz wide-band CDMA(W-CDMA) handsets. The HJFET has a 5nm thickness Al_<0.5>Ga_<0.5>As barrier layer for improving a gate forward turn-on voltage. It was also optimized with thickness of upper and lower Al_<0.2>Ga_<0.8>As electron supply layers to obtain a high maximum drain current. Under single 3.5V operation, the two-stage power amplifier MCM exhibited 26.0dBm output power, a record 47.2% power-added efficiency(PAE) and 22.3dB associated gain at W-CDMA distortion criteria. Even operated at a reduced operation voltage of 2.0V, a high PAE of 46% was achieved. These results indicated the developed MCM is promising for W-CDMA handsets.

  • Power Module for W-CDMA Handsets Utilizing Enhancement-Mode Heterojunction FETs

    Bito Y., Kato T., Kato T., Iwata N.

    Proceedings of the Society Conference of IEICE   2000 ( 2 )   61 - 61   2000.9

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    Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

  • C-10-14 Linearized Variable Gain Amplifier and Power Amplifier MMICs for 1.95 GHz W-CDMA Handsets

    Hau Gary, Nishimura Takeshi B., Iwata Naotaka

    Proceedings of the Society Conference of IEICE   2000 ( 2 )   66 - 66   2000.9

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    Language：English   Publisher：The Institute of Electronics, Information and Communication Engineers  

  • InGaP/GaAs HBT Power Module for 1.9 GHz CDMA Handsets

    Nishimura T.B., Tomita M., Bito Y., Hau G., Tanomura M., Miyoshi Y., Harima F., Azuma K., Shimawaki H., Iwata N.

    Proceedings of the Society Conference of IEICE   2000 ( 2 )   60 - 60   2000.9

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    Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

  • L-Band 100W High Voltage Operation Field-Modulating Plate HFET

    Sakura N., Ishikura K., Takenaka I., Asano K., Matsunaga K., Iwata N., Kanamori M., Kuzuhara M.

    Proceedings of the IEICE General Conference   2000 ( 2 )   72 - 72   2000.3

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    Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

  • A linearized Power Amplifier MMIC for W-CDMA Handsets

    Hau Gary, Nishimura Takeshi B., Iwata Naotaka

    Proceedings of the IEICE General Conference   2000 ( 2 )   77 - 77   2000.3

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    Language：English   Publisher：The Institute of Electronics, Information and Communication Engineers  

  • W-CDMA Power Performance of Enhancement-Mode Heterojunction FET Utilizing Al_<0.5>Ga_<0.5>As Barrier Layer

    Bito Y., Kato T., Tomita M., Iwata N.

    Proceedings of the IEICE General Conference   2000 ( 2 )   79 - 79   2000.3

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    Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

  • A Linearized Heterojunction FET-Based Power Amplifier with High Efficiency over Wide Output Power Range for Wide-Band CDMA Handsets

    NISHIMURA Takeshi B., IWATA Naotaka, HAU Gary

    IEICE technical report. Electron devices   99 ( 555 )   41 - 46   2000.1 （   ISSN:0913-5685 ）

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    Language：English   Publisher：The Institute of Electronics, Information and Communication Engineers  

    A linearized power amplifier with high efficiency over wide output power range has been developed for 1.95 GHz wide-band CDMA handsets.An MMIC predistorter was incorporated into a heterojunction FET-based amplifier for improving the linearity and efficiency.Measured at an adjacent channel leakage power ratio(ACPR)of -40 dBc, the output power(P_out)and power added efficiency(PAE)of the amplifier improve from 25.5 dBm and 54.4% to 26.2 dBm and 57.4% respectively after the use of predistorter under 3.5 V operation.With bias control, the linearized amplifier also shows an excellent low P_out(13 dBm)performance, achieving a PAE of 47.7% at the same ACPR level.The linearized amplifier achieves a PAE over 40% over an output power range of 21 dB, making it suitable for wide dynamic range W-CDMA handset application.

  • InGaP/GaAs HBT Power Amplifier for Mobile Handsets(I) : Re1iability and Power Performance for 1.9-GH_z CDMA Applications

    Tanomura M., Miyoshi Y., Kawanaka M., Nishimura T.B., Harima H., Sato H., Takahashi H., Yoshida S., Azuma K., Iwata N., Shimawaki H.

    Proceedings of the Society Conference of IEICE   2   59 - 59   2000

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    Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

  • Wide-Band CDMA Distortion Characteristics of an AlGaAs/InGaAs/AlGaAs Heterojunction FET under Various Quiescent Drain Current Operations

    HAU Gary, NISHIMURA Takeshi, IWATA Naotaka

    IEICE transactions on electronics   82 ( 11 )   1928 - 1935   1999.11 （   ISSN:0916-8524 ）

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    Language：English   Publisher：The Institute of Electronics, Information and Communication Engineers  

    Wide-band CDMA (W-CDMA) distortion characteristics of a fabricated double-doped heterojunction FET (HJFET) are presented. Measured results demonstrate that the first and second adjacent channel W-CDMA adjacent channel leakage power ratios (ACPRs) of the HJFET are correlated to the third-and fifth-order intermodulation (IM3 and IM5) distortions respectively under various quiescent drain current operation (I_q). A first channel ACPR dip phenomenon is observed under a low I_q. condition, resulting in improved power added efficiency. Due to its close correlation to the IM3 distortion, the ACPR dip phenomenon is explained in terms of the similar IM3 characteristic. Simulated results reveal that the dip is a consequence of the cancellation of distortions generated by the third-and fifth-order nonlinearities at the IM3 frequency. The conditions for the cancellation are detailed.

  • A CW 4 Watt Ka-Band Power Amplifier Utilizing MMIC Multi-Chip Technology

    MATSUNAGA K., MIURA I., IWATA N.

    IEICE technical report. Electron devices   99 ( 440 )   21 - 27   1999.11 （   ISSN:0913-5685 ）

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    This paper describes design consideration and performances of a Ka-band power amplifier. The amplifier utilizes four fully-matched MMICs, in which 0.35μm-long gate GaAs-based heterojunction FETs are employed. The developed power MMIC amplifier delivered an output power of 1.0W at 28GHz. Same matching circuits with easy configuration are applicable for both input and output matching circuits by combining four fully-matched MMICs. The power amplifier demonstrated an output power of 3.0W and a power-added efficiency of 20.5%. The highest output power of 4.5W was achieved. The developed power amplifier also provides the highest CW output power of 3.0W over the bandwidth of 2GHz at Ka-band.

  • C-10-10 A Predistorter for Improving the Linearity of a Heterojunction FET Amplifier for W-CDMA Handsets

    Hau Gary, Nishimura Takeshi B., Iwata Naotaka

    Proceedings of the Society Conference of IEICE   1999 ( 2 )   47 - 47   1999.8

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  • L-Band 50W High Voltage Operation of Field-Modulating Plate HFET

    Sakura N., Ishikura K., Asano K., Matsunaga K., Iwata N., Kanamori M., Kuzuhara M.

    Proceedings of the Society Conference of IEICE   1999 ( 2 )   44 - 44   1999.8

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  • Performance of a Heterojunction FET Amplifier with a Predistorter under W-CDMA Criteria

    Nishimura Takeshi B., Hau Gary, Iwata Naotaka

    Proceedings of the Society Conference of IEICE   1999 ( 2 )   48 - 48   1999.8

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  • High Efficiency Operation of Power Heterojunction FET with Drain Bias Supply Control of less than 3.5V for W-CDMA Handsets

    IWATA Naotaka, NISHIMURA Takeshi B., KATO Takehiko, TOMITA Masatoshi, BITO Yasunori, HAU Gary

    IEICE technical report. Electron devices   99 ( 146 )   77 - 82   1999.6 （   ISSN:0913-5685 ）

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    This paper describes W-CDMA power performance of a double-doped heterojunction FET (HJFET) with a novel multilayer cap. With an optimum impedance matching at a reduced quiescent drain current (I_q) of 50mA and a drain bias voltage of 3.5V, the HJFET with a 19.2mm gate width exhibited a power added efficiency (PAE) of 54% with an output power (P_<out>) of 570mW at an adjacent channel leakage power ratio of -40dBc. Utilizing a DC-DC converter as a drain bias supply of 1.0V, the amplifier achieved 21% PAE at 20mW P_<out>. The HJFET under low I_q operation with a DC-DC converter is promising for power amplifier application of the W-CDMA handsets.

  • SC-10-5 Simulation of Distortion Characteristics of a Heterojunction FET under Wide-Band CDMA Criteria

    Gary Hau, Nishimura Takeshi, Iwata Naotaka

    Proceedings of the IEICE General Conference   1999 ( 1 )   447 - 448   1999.3

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  • High Efficiency Operation over Wide Range Output Power of HJFET for Wide-Band CDMA Cellular Phones

    Nishimura Takeshi B., Hau Gary, Tomita Masatoshi, Iwata Naotaka

    Proceedings of the IEICE General Conference   1999 ( 2 )   75 - 75   1999.3

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  • C-10-4 Correlation between Wide-Band CDMA Distortion Characteristics and Intermodulation Distortions of a Heterojunction FET

    Hau Gary, Nishimura Takeshi B., Iwata Naotaka

    Proceedings of the IEICE General Conference   1999 ( 2 )   76 - 76   1999.3

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  • High Voltage Operation Power Heterojunction HJFET with Field-Modulating Plate

    Sakura N., Matsunaga K., Iwata N., Kuzuhara M.

    Proceedings of the IEICE General Conference   1999 ( 2 )   80 - 80   1999.3

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  • A Ka-Band 1 W high power MMIC amplifier

    Matsunaga K., Miura I., Iwata N.

    Proceedings of the IEICE General Conference   1999 ( 1 )   89 - 89   1999.3

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  • V-band power amplifier with increased stability at intermediate frequencies

    Inoue Takashi, Iwata Naotaka, Ohata Keiichi

    Proceedings of the IEICE General Conference   1999 ( 1 )   95 - 95   1999.3

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  • SC-10-5 Simulation of Distortion Characteristics of a Heterojunction FET under Wide-Band CDMA Criteria

    Hau Gary, Nishimura Takeshi B., Iwata Naotaka

    Proceedings of the IEICE General Conference   1999 ( 2 )   233 - 234   1999.3

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  • Low Voltage Operation Power Heterojunction FET with Low on-resistance for Personal Digital Cellular Phones

    KATO Takehiko, BITO Yasunori, IWATA Naotaka

    IEICE technical report. Microwaves   98 ( 522 )   13 - 18   1999.1

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    This paper describes excellent 1.0V operation power performance of a double doped AlGaAs/InGaAs/AlGaAs heterojunction FET(HJFET)for Personal Digital Cellular Phones. A low on-resistance of a power FET is key issue for a high output power and a high efficiency. The developed FET with a multilayer cap consisting of a highly Si-doped AlGaAs and narrow recessed structure exhibited an on-resistance of 1.3Ω・mm and a maximum drain current of 620mA/mm. A 28mm gate-periphery device operating with a drain bias voltage of 1.0V demonstrated an output power of 1.0W, an associated gain of 13.7dB and a power-added efficiency of 59% with an adjacent channel leakage power at 50kHz off-center frequency of -48dBc.

  • 1.1V Operation Power Heterojunction FETs for Personal Digital Cellular Phones

    Kato Takehiko, Bito Yasunori, Iwata Naotaka

    Proceedings of the Society Conference of IEICE   1998 ( 2 )   50 - 50   1998.9

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  • Proposed Double-Doped Power Metamorphic HJFET for Low Voltage Operation

    Contrata W., Iwata N., Samoto N.

    Proceedings of the Society Conference of IEICE   1998 ( 2 )   68 - 68   1998.9

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  • Low On-Resistance Enhancement-Mode Power Heterojunction FET for 3.5V Operation Personal Digital Cellular Phones

    Bito Y., Iwata N.

    Proceedings of the Society Conference of IEICE   1998 ( 2 )   53 - 53   1998.9

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  • 3.5V Operation Power HJFET with 44% Efficiency for Wide-Band CDMA Cellular Phones

    Nishimura T.B., Bito Y., Tomita T., Hau Gary, Iwata N.

    Proceedings of the Society Conference of IEICE   1998 ( 2 )   49 - 49   1998.9

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  • Single 1.5 V Operation Power Amplifier MMIC with SrTiO_3 Capacitors for 2.4 GHz Wireless Applications

    B. NISHIMURA Takeshi, IWATA Naotaka, YAMAGUCHI Keiko, TOMITA Masatoshi, BITO Yasunori, TAKEMURA Koichi, MIYASAKA Yoichi

    IEICE Trans. Electron., C   81 ( 6 )   898 - 903   1998.6 （   ISSN:0916-8524 ）

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    This paper describes design approach and power performance of a single 1.5V operation two-stage power amplifier MMIC for 2.4GHz wireless local area network applications. The MMIC with 0.76×0.96mm^2 area includes SrTiO_3(STO)capacitors with a high capacitance density of 8.0fF/μm^2 and double-doped AlGaAs/InGaAs/AlGaAs heterojunction FETs with a shallow threshold voltage of-0.24V. Utilizing a series STO capacitor and a shunt inductor as an output matching circuit, the total chip size was reduced by 40% as compared with an MMIC utilizing SiN_x capacitors. Under single 1.5V operation, the developed MMIC delivered an output power of 110mW(20.4dBm)and a power-added efficiency(PAE)of 36.7% with an associated gain of 20.0dB at 2.4GHz. Even operated at a drain bias voltage of 0.8V, the MMIC exhibited a high PAE of 31.0%.

  • A Report on 1997 Asia-Pacific Microwave Conference

    ITOH Yasushi, IWATA Naotaka, KAWAI Tadashi, KAWASAKI Shigeo, KUROKI Futoshi, SANAGI Minoru

    IEICE technical report. Microwaves   98 ( 74 )   77 - 83   1998.5

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    The 9^<th> Asia Pacific Microwave Conference was held from 2^<nd> December to 5^<th> December on campus of the City University of Hong Kong, Hong Kong, where 304 papers were presented including 19 invited papers. This report covers topics on electromagnetic field theory, guided waves, active devices and circuits, antenna, microwave system applications, CAD, microwave measurement, optical devices and systems, and super-conductor.

  • 3.5V Operation Amplifer MMIC Utilizing SrTiO_3 Capacitors for Wide-Band CDMA Cellular Phones

    Nishimura T.B., Iwata N., Yamaguchi K., Takemura K., Miyasaka Y.

    Proceedings of the IEICE General Conference   1998 ( 2 )   100 - 100   1998.3

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  • 64% Efficiency Enhancement-Mode Power Heterojunction FET for 3.5V Li-Ion Battery Operated Personal Digital Cellular Phones

    Bito Y., Iwata N., Tomita M.

    Proceedings of the IEICE General Conference   1998 ( 2 )   103 - 103   1998.3

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  • Power Amplifier MMICs Utilizing SrTiO_3 Capacitors For Mobile Communication Systems

    NISHIMURA Takeshi B., IWATA Naotaka, YAMAGUCHI Keiko, TOMITA Masatoshi, TAKEMURA Koichi, MIYASAKA Yoichi

    IEICE technical report. Microwaves   97 ( 477 )   21 - 26   1998.1

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    We fabricated two-stage power amplifier MMICs utilizing double-doped heterojunction FETs and SrTiO_3 capacitors for personal digital cellular (PDC), Code division multiple access (CDMA) and wireless local area network (WLAN) sytems, respectively. The MMIC amplifiers include matching and bias circuits. For 950MHz PDC applications, the 2.0×2.4mm^2 MMIC delivered 0.8W output power (P_<out>), 30% power-added efficiency (PAE) and 26.4dB associated gain (G_a) with -50.5dBc adjacent channel leakage power at 50kHz off-center frequency under 3.4V operation. For 840MHz CDMA applications, the 2.0×1.5mm^2 MMIC delivered 0.93W P_<out>, 48.6% PAE and 28.4dB G_a at the IS-95 criteria. For 2.48GHz WLAN applications, the 0.76×0.96mm^2 MMIC achieved 182mW P_<out>, 33.2% PAE and 22.7dB G_a with single 2.2V DC supply.

  • 50% High Efficiency 1W Power Heterojunction FET for 3.5V CDMA Cellular Phones

    Yamaguchi K., Tomita M., Iwata N.

    Proceedings of the Society Conference of IEICE   1997 ( 2 )   35 - 35   1997.8

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  • Single 3.4V Operation Heterojunction FET for Personal Digital Cellular Phones

    Bito Y., Tomita M., Yamaguchi K., Nishimura T., Iwata N.

    Proceedings of the Society Conference of IEICE   1997 ( 2 )   34 - 34   1997.8

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  • Single Voltage Operation MMIC Power Amplifier for 1.95GHz CDMA Applications

    Nishimura T.B., Iwata N., Yamaguchi K., Tomita M., Bito Y., Takemura K., Miyasaka Y.

    Proceedings of the Society Conference of IEICE   1997 ( 2 )   37 - 37   1997.8

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  • 3.5V Operation High Efficiency MMIC Power Amplifier for CDMA Cellular Phones

    Yamaguchi K., Iwata N., Nishimura T.B., Tomita M., Takemura K., Miyasaka Y.

    Proceedings of the Society Conference of IEICE   1997 ( 2 )   36 - 36   1997.8

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  • Small-Sized 1W MMIC Power Amplifier Operated at 3.4 V for Digital Cellular Phones

    Yamaguchi K., Nishimura T. B., Iwata N., Takemura K., Kuzuhara M., Miyasaka Y.

    Proceedings of the IEICE General Conference   1997 ( 2 )   92 - 92   1997.3

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  • Small-Sized Power Heterojunction FETs for Low-Voltage Digital Cellular Applications

    Iwata N., Yamaguchi K., Tomita M., Bito Y., Kuzuhara M.

    Proceedings of the IEICE General Conference   1997 ( 2 )   286 - 287   1997.3

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  • Single 0.2 V Operation MMIC Power Amplifier with STO Capacitors for WLAN Applications

    NISHIMURA T.B., Yamaguchi K., IWATA N., TOMITA M., TAKEMURA K., KUZUHARA M., MIYASAKA Y.

    Proceedings of the IEICE General Conference   1997 ( 2 )   95 - 95   1997.3

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  • Small-Sized Power Heterojunction FETs for 3.4V Digital Cellular Applications

    IWATA Naotaka, TOMITA Masatoshi, YAMAGUCHI Keiko, OIKAWA Hirokazu, KUZUHARA Masaaki

    IEICE technical report. Electron devices   96 ( 462 )   15 - 18   1997.1

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    This paper describes 950MHz power performance of a 7.0mm gate width (W_g) n-AlGaAs/InGaAs/n-AlGaAs heterojunction FET(HJFET) for personal digital cellular phones. The fabricated HJFET with a 0.8μm long WSi gate exhibited 2.3Ω・mm on-resistance, 640mA/mm maximum drain current, 330mS/mm transconductance and 12.7V gate-to-drain breakdown voltage. Operated with a drain bias of 3.4V, the HJFET demonstrated 1.23W(30.9dBm) output power and 56.3% power-added efficiency with -51.5dBc adjacent channel leakage power at 50kHz off-center frequency. We also discussed on power performance dependence on W_g using a class analysis.

  • 7mm Gate Width PDC Power Heterojunction FETs Operation at 3.4V

    Iwata N, Tomita M, Yamaguchi K, Oikawa H, Kuzuhara M

    Proceedings of the Society Conference of IEICE   1996 ( 2 )   76 - 76   1996.9

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  • Pt Schottky Gate InP MESFET with High Drain Current

    Bito Yasunori, Iwata Naotaka, Kuzuhara Masaaki

    Proceedings of the Society Conference of IEICE   1996 ( 2 )   78 - 78   1996.9

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  • 1.2V Operation Power Heterojunction FETs for Personal Digital Cellular Phones

    YAMAGUCHI Keiko, IWATA Naotaka, KUZUHARA Masaaki

    Proceedings of the Society Conference of IEICE   1996 ( 2 )   75 - 75   1996.9

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  • 1.2V Operation Power Heterojunction FETs for Personal Digital Cellular Phones

    YAMAGUCHI Keiko, IWATA Naotaka, KUZUHARA Masaaki

    IEICE technical report. Electron devices   96 ( 108 )   39 - 44   1996.6

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    This paper describes 950MHz power performance for double-doped heterojunction FETs(HJFETs) operated at 1.2V, which corresponds to the voltage of one NiMH battery cell. The fabricated HJFET with a 0.8μm long gate, which was off-set towards source side, exhibited a maximum drain current (I_<max>) of 640mA/mm, a transconductance of 340mS/mm and a on-resistance of 2.12Ωmm. A 950MHz π/4-shifted QPSK output signal of 1.15W and 39% power-added efficiency was demonstrated with an adjacent channel leakage power at 50kHz off-center frequency of 49.3dBc for an HJFET with W_g=38.5mm. This high performance under 1.2V operation is ascribed to the high I_<max> as well as a low effective knee voltage for the developed HJFET with a source-to-gate recessed length of 0.5μm.

  • 1.2V Operation 1.1W Power Double-Doped Heterojunction FETs

    Yamaguchi Keiko, Iwata Naotaka, Kuzuhara Masaaki

    Proceedings of the IEICE General Conference   1996 ( 2 )   99 - 99   1996.3

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  • 3.4V Operation Power Amplifier Multi-chip IC's for Digital Cellular Phone

    HASEGAWA Yasuaki, OGATA Yukinori, YAMAGUCHI Keiko, IWATA Naotaka, KANAMORI Mikio, ITOH Tomohiro

    IEICE technical report. Electron devices   95 ( 449 )   79 - 83   1996.1

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    GaAs power multi-chip IC (MCIC) operating at 3.4V for digital cellular phone has been developed. This MCIC employs a double-doped heterojunction FET (HJFET). The MCICs can deliver an output power over 31.2dBm with a power-added efficiency of 46% from 1429 to 1453MHz. And this MCIC has low distortion, the adjacent channel interference of the π/4-shift QPSK signal is -53dBc at the +50KHz apart from the center frequency. The volume of the MCIC is only 0.4cc, half that of conventional power MCICs, These MCICs will contribute to realization of compact cellular phones.

  • 1.2V Operation 1.1W Heterojunction FETs for Portable Radio Applications

    YAMAGUCHI Keiko, IWATA Naotaka, KUZUHARA Masaaki

    IEICE technical report. Electron devices   95 ( 448 )   7 - 12   1996.1

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    This paper describes 950MHz power performance for double-doped heterojunction FETs(HJFETs) operated at a low drain bias voltage of 1.2V, which corresponds to the voltage of one NiMH battery. The fabricated 28mm gate HJFET achieved 1.1W saturated output power and 63%maximum power-added efficiency. The load-pull measurement at 1.2V operation indicated that the optimum impedances for maximum output power and maximum PAE were similar to each other. The saturated output power calculation using Fourier series expansion revealed that output power increases with an increase in the load impedance, resulting from a large swing of the drain voltage. As a result, when the operating drain voltage is very small, higher power and higher PAE can be simultaneously achieved with a similar load impedance value.

  • Power Heterojunction FETs for Low-Voltage Digital Cellular Applications

    INOSAKO Keiko, IWATA Naotaka, KUZUHARA Masaaki

    IEICE Trans. Electron., C   78 ( 9 )   1241 - 1245   1995.9 （   ISSN:0916-8524 ）

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    This paper describes 950 MHz power performance of double-doped AlGaAs/InGaAs/AlGaAs heterojunction field-effect transistors (HJFET) operated at a drain bias voltage ranging from 2.5 to 3.5 V. The developed 1.0μm gate-length HJFET exhibited a maximum drain current (I_ltmaxgt) of 500 mA/mm, a transconductance (g_m) of 300 mS/mm, and a gate-to-drain breakdown voltage of 11 V. Operated at 3.0 V, a 17.5 mm gate periphery HJFET showed 1.4 W P_ltoutgt and -50.3 dBc adjacent channel leakage power at a 50kHz off-carrier frequency from 950 MHz with 50% PAE. Harmonic balance simulations revealed that the flat g_m characteristics of the HJFET with respect to gate bias voltage are effective to suppress intermodulation distortion under large signal operation. The developed HJFET has great potential for small-sized digital cellular power applications operated at a low DC supply voltage.

  • 1.5v Operation 1W Power Doubie-Doped Heterojunction FETs

    Inosako Keiko, Iwata Naotaka, Kuzuhara Masaaki

    Proceedings of the Society Conference of IEICE   1995 ( 2 )   93 - 93   1995.9

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  • Power Heterojunction FETs Operating with a Single Low-Voltage Supply

    IWATA Naotaka, INOSAKO Keiko, KUZUHARA Masaaki

    Proceedings of the Society Conference of IEICE   1995 ( 2 )   94 - 94   1995.9

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  • 2V Operation Small-Sized Double-Doped Heterojunction FETs for Portable Radio Applications

    INOSAKO Keiko, IWATA Naotaka, KUZUHARA Masaaki

    Proceedings of the IEICE General Conference   1995 ( 2 )   143 - 143   1995.3

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  • Low-Voltage Operated Heterojunction FETs for PDC Power Application

    IWATA Naotaka, INOSAKO Keiko, KUZUHARA Masaaki

    Proceedings of the IEICE General Conference   1995 ( 2 )   262 - 263   1995.3

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  • 3V Operation Power Heterojunction FETS for Cigital Cellular Applications

    Inosako Keiko, Iwata Naotaka, Kuzuhara Masaaki

    1994 ( 2 )   122 - 122   1994.9

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Presentations

  • Annealing in Oxygen ambient of In-based contact for Mg-doped p-GaN

    Maria Emma Castil Villamin, Naotaka Iwata

    2024.3 

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    Event date： 2024.3

    Presentation type：Poster presentation  

  • ArF excimer laser activation of Mg-doped GaN small area mesa device International conference

    Maria Emma Castil Villamin, Naotaka Iwata

    SPIE Photonics West 2024  ( Moscone Center , San Francisco, CA )   2024.1 

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    Event date： 2024.1 - 2024.2

    Presentation type：Poster presentation  

  • エネルギーハーベスティングからワイヤレス電力伝送に適用できるGaNヘテロ構造整流ダイオードの研究開発 Invited

    岩田直高

    早稲田大学アンビエントロニクス研究所 × ワイヤレス電力伝送実用化コンソーシアム × エネルギーハーベスティングコンソーシアム ジョイントシンポジウム  ( 早稲田大学 )   2023.12 

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    Event date： 2023.12

    Presentation type：Oral presentation (invited, special)  

  • Formation of In/Au low-temperature contact for vertical superjunction GaN devices with laser-activated p-GaN region International conference

    Maria Emma Villamin, Naotaka Iwata

    International Conference on Nitride Semiconductors (ICNS-14)  2023.11 

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    Event date： 2023.11

    Presentation type：Poster presentation  

  • Annealing temperature dependence of In/Au electrode performance on p-GaN

    Maria Emma Castil Villamin, Naotaka Iwata

    2023.9 

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    Event date： 2023.9

    Presentation type：Poster presentation  

  • N2/O2雰囲気アニールによるAu/Ni/p-GaNオーム性接触の低抵抗化

    岩田直高,三明純奈,Maria Emma Villamin

    電子情報通信学会ソサイエティ学会  ( 名古屋大学 )   2023.9 

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    Event date： 2023.9

    Presentation type：Oral presentation (general)  

  • GaN Heterojunction Rectifier Diode with Low Turn-On Voltage and High Breakdown Voltage for Energy Harvesting International conference

    Naotaka Iwata, Kouki Hino, Maria Emma Castil Villamin

    2023 International Conference on Solid State Devices and Materials(SSDM2023)  2023.9 

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    Event date： 2023.9

    Presentation type：Poster presentation  

  • Unveiling the role of trimethylaluminum in passivating InAs surface quantum dots International conference

    Hanif Mohammadi, Ronel Christian Roca, Hyunju Lee, Yoshio Ohshita, Naotaka Iwata, Itaru Kamiya

    55th annual SSDM international conference  ( 55th annual SSDM international conference )   2023.9 

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    Presentation type：Oral presentation (general)  

  • 低オン電圧高電流特性を示す環境発電用GaNヘテロ接合整流ダイオード

    日野晃貴、マリア　エマ　ヴィリアミン、岩田直高

    第70回応用物理学会春季学術講演会  ( 上智大学 )   2023.3 

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    Event date： 2023.3

    Presentation type：Poster presentation  

  • Comparison of thermal and ArF excimer laser activation of Mg-doped GaN

    Maria Emma Castil Villamin, Naotaka Iwata

    2023.3 

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    Event date： 2023.3

    Presentation type：Poster presentation  

  • Diethylzinc passivation of InAs surface quantum dots International conference

    Hanif Mohammadi*, Ronel Christian Intal ROCA, Hyunju Lee*, Naotaka Iwata, Yoshio Ohshita, Itaru Kamiya

    2023年春季第70回応用物理学関係連合講演会  ( 上智大学 )   2023.3  応用物理学会

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    Presentation type：Oral presentation (general)  

    ALDにおいて、ジエチル亜鉛を用いたInAs量子ドットのパッシベーション効果に関する報告。

  • Drain current lag characterization of Fe- and C-doped GaN buffer HEMTs on GaN substrates International conference

    Maria Emma Villamin, Naotaka Iwata

    the 15th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials (ISPlasma2023)  2023.3 

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    Event date： 2023.3

    Presentation type：Poster presentation  

  • PL enhancement of InAs surface quantum dots by ex situ DEZ/ZnO passivation capping International conference

    Hanif Mohammadi*, Ronel Christian Intal ROCA, Yuwei Zhang*, Hyunju Lee*, Naotaka Iwata, Yoshio Ohshita, Itaru Kamiya

    2022年第83回応用物理学会秋季学術講演会  ( 東北大学川内北キャンパス（オンライン） )   2022.9  応用物理学会

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    Presentation type：Oral presentation (general)  

    ALD法によるDEZを用いたInAs量子ドットのパッシベーション被覆によるPL発光強度の増強に関する報告。

  • Photoluminescence enhancement of InAs surface quantum dots by Al2O3 passivation International conference

    Hanif Mohammadi*, Ronel Christian Intal ROCA, Yuwei Zhang*, Hyunji Lee*, Yoshio Ohshita, Naotaka Iwata, Itaru Kamiya

    春季第69回応用物理学関係連合講演会  ( 青山学院大学相模原キャンパス )   2022.3  応用物理学会

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    Photoluminescence enhancement of InAs surface quantum dots by Al2O3 passivation using atomic layer deposition was reported.

  • Conduction change of Mg and Si co-doped GaN layer by ArF laser irradiation International conference

    Ryuji Kamiya*, Yukari Yonetani*, ジャン　ユーウェイ, Itaru Kamiya*, Noriko Kurose **, Yoshinobu Aoyagi **, Naotaka Iwata

    the 14th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials (ISPlasma2022)  ( Online )   2022.3 

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    08ｐC08O

  • High breakdown voltage of p-GaN/AlGaN/GaN diode with controlled Mg acceptor charges International conference

    Soichiro Kawata*, Satoshi Fukutani*, ジャン　ユーウェイ, Naotaka Iwata

    the 14th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials (ISPlasma2022)  ( Online )   2022.3 

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    07pD10O

  • Low turn-on voltage rectifier using p-GaN gate AlGaN/GaN high electron mobility transistor for energy harvesting applications International conference

    ジャン　ユーウェイ, Soichiro Kawata*, Naotaka Iwata

    第82回応用物理学会秋季学術講演会  ( Online )   2021.9 

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    オーラル　13a-N305-3

  • MgドープGaN層の厚さを変えて電荷濃度を制御したp型GaN/AlGaN/GaNダイオードの耐圧特性 International conference

    川田 宗一郎*, ジャン　ユーウェイ, 岩田　直高

    第82回応用物理学会秋季学術講演会   ( Online )   2021.9 

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    オーラル　12p-N305-4

  • Two-step mesa p-GaN gated anode diode for low-power rectification applications International conference

    ジャン　ユーウェイ, Naotaka Iwata

    2021 International Conference on Solid State Devices and Materials(SSDM2021)  ( Online )   2021.9 

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    オーラル　D-7-03

  • High breakdown voltage InGaAs/AlGaAs/InGaAs superjunction devices with modulation-doping for on-resistance reduction International conference

    Hiroaki Ogawa*, Naotaka Iwata

    2021 International Conference on Solid State Devices and Materials(SSDM2021)  ( Online )   2021.9 

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    オーラル　D-2-06

  • 変調ドープによる電子正孔がGaAsまたはInGaAsチャネルに形成されたヘテロ接合デバイスの特性 International conference

    尾川弘明*, 豊原真由*, 浅賀圭太*, 岩田　直高

    2021年第68回応用物理学会春季学術講演会  ( Online )   2021.3 

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    オーラル　19p-Z25-8

  • Comparison of side-gate modulation responses for AlGaN/GaN HEMTs on GaN substrates with and without C-doped GaN buffer layer International conference

    VILLAMIN, Maria Emma C., Naotaka Iwata

    2021年第68回応用物理学会春季学術講演会  ( Online )   2021.3 

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    ポスター　19p-PO6-8

  • P-GaN gated AlGaN/GaN diode for rectification applications International conference

    Soichiro Kawata*, Hinano Kondo*, ジャン　ユーウェイ, Naotaka Iwata

    the 13th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials (ISPlasma2021)  ( Online )   2021.3 

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    ポスター　10P-21

  • P-GaN gate AlGaN/GaN high electron mobility transistor with nearly-zero threshold voltage for power rectification applications International conference

    ジャン　ユーウェイ, Naotaka Iwata

    the 13th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials (ISPlasma2021)  ( Online )   2021.3 

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    オーラル　10aD06O

  • Controlled activation of Mg dopant by laser irradiation for p-GaN formation International conference

    Ryuji Kamiya*, Takahito Ichinose*, ジャン　ユーウェイ, Noriko Kurose National Center of Neurology and Psychiatry**, Itaru Kamiya, Yoshinobu Aoyagi Ritsumeikan University**, Naotaka Iwata

    the 13th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials (ISPlasma2021)  ( Online )   2021.3 

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    ポスター　10P-14

  • Effect of side-gate modulation on AlGaN/GaN HEMTs on GaN substrates with different GaN channel and buffer thicknesses International conference

    VILLAMIN, Maria Emma C., Naotaka Iwata

    the 13th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials (ISPlasma2021)  ( Online )   2021.3 

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    ポスター　10P-20

  • Effect of C- and Fe-doped GaN Buffer on AlGaN/GaN HEMT Performance on GaN Substrate Using Side-gate Modulation International conference

    VILLAMIN, Maria Emma C., Takaaki Kondo*, Naotaka Iwata

    2020年国際固体素子・材料コンファレンス(SSDM2020)  ( Online )   2020.9 

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    オーラル　D-7-06

  • 1.8kV AlGaAs/GaAs/AlGaAs Diode Having Balanced Charges of Donors and Acceptors in Consideration of Residual Carbon Impurities International conference

    Hiroaki Ogawa*, Soichiro Kawata*, Naotaka Iwata

    2020年国際固体素子・材料コンファレンス(SSDM2020)  ( Online )   2020.9 

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    オーラル　D-5-01

  • Side gate modulation of AlGaN/GaN HEMTs on GaN with C and Fe doped buffers International conference

    VILLAMIN, Maria Emma C., Takaaki Kondo*, Naotaka Iwata

    第81回応用物理学会秋季学術講演会  ( Online )   2020.9  応用物理学会

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    オーラル　10p-Z04-6

  • 不純物濃度を揃えて電子正孔チャネルを形成したAlGaAs/GaAs/AlGaAsヘテロ接合ダイオードの高耐圧特性 International conference

    尾川弘明*, 川田宗一郎*, 櫛田知義 トヨタ自動車株式会社**, 岩田　直高

    第67回応用物理学会春季学術講演会  ( （上智大学　四ツ谷キャンパス） )   2020.3  応用物理学会

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    ポスター　13p-PA9-22

  • GaN基板上AlGaN/GaN HEMTの素子特性に バッファ層へのCまたはFeドーピングが及ぼす影響 International conference

    近藤孝明*, 東中川洋幸*, 岩田　直高

    第67回応用物理学会春季学術講演会  ( （上智大学　四ツ谷キャンパス） )   2020.3  応用物理学会

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    ポスター　13p-PA9-16

  • High-selectivity dry etching for p-GaN gate formation of normally-off operation high electron mobility transistor International conference

    Naotaka Iwata, Takaaki Kondo*

    12th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials (ISPlasma 2020)　  ( （名古屋大学） )   2020.3 

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    ポスター　11P4-05

  • Formation of ohmic contact to p-type GaN by heat treatment of Au/Ni electrode International conference

    So Kuroyanagi*, Satoshi Yasuno **, Takaaki Kondo*, Tomoyuki Koganezawa **, Naotaka Iwata

    12th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials(ISPlasma 2020)  ( （名古屋大学） )   2020.3 

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    ポスター　11P4-04

  • Characterization of Au/Ni ohmic contact on p-GaN using hard X-ray photoelectron spectroscopy and 2D-X-ray diffraction International conference

    Satoshi Yasuno **, Tomoyuki Koganezawa **, So Kuroyanagi*, Naotaka Iwata

    Materials Research Meeting 2019  ( 横浜シンポジア )   2019.12 

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    ポスター　G5-13-P03

  • Au/Ni/p-GaNオーミックコンタクトの熱処理温度依存性とバンドアライメント評価 International conference

    安野聡 高輝度光科学研究センター**, 畔柳壮*, 小金澤智之 高輝度光科学研究センター**, 岩田　直高

    先進パワー半導体分科会 第6回講演会  ( 広島国際会議場 )   2019.12  応用物理学会

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    ポスター　ⅡB-20

  • p型GaN上に形成したAu/Ni電極の熱処理による低接触抵抗化 International conference

    畔柳壮*, 近藤孝明*, 安野聡 高輝度光科学研究センター**, 小金澤智之 高輝度光科学研究センター**, 岩田　直高

    第80回応用物理学会秋季学術講演会  ( 北海道大学 )   2019.9  応用物理学会

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    ポスター　19p-PB3-22

  • Effects of p-GaN gate structures and their fabrication process on performances of normally-off AlGaN/GaN HEMTs International conference

    Takaaki Kondou*, Yoshihiko Akazawa*, Naotaka Iwata

    11th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials (ISPlasma2019)  ( Nagoya, Japan )   2019.3  応用物理学会

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    Effects of p-GaN gate structures and their fabrication process on performances of normally-off AlGaN/GaN HEMTs

  • 様々なp型GaNゲート構造をドライエッチングで形成したAlGaN/GaNGaNGaN高電子移動度トランジスタの特性 International conference

    近藤孝明*, 赤澤良彦*, 岩田　直高

    第66回応用物理学会春季学術講演会  ( 東京工業大学 )   2019.3  応用物理学会

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    様々なp型GaNゲート構造をドライエッチングで形成したAlGaN/GaNGaNGaN高電子移動度トランジスタの特性

  • 1対の電子チャネルと正孔チャネルを有するAlGaAs/GaAs/AlGaAsヘテロ構造ダイオードの耐圧特性 International conference

    尾川弘明 電子デバイス*, 大保嵩博 電子デバイス*, 田浦成幸 電子デバイス*, 櫛田知義*, 岩田　直高

    第66回応用物理学会春季学術講演会  ( 東京工業大学 　大岡山キャンパス 2019/3/9-3/12 )   2019.3  応用物理学会

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    ポスター発表　11p-PB3-27

  • Laser-induced local activation of Mg-doped GaN and AlGaN for high power vertical devices Invited International conference

    Noriko Kurose Ritsumeikan Univ.*, Naotaka Iwata, Itaru Kamiya

    SPIE Photonics West 2019  ( San Francisco, California, USA )   2019.2  SPIE

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  • Effect of inductively coupled plasma reactive ion etching on performances of p-GaN gate AlGaN/GaN HEMTs International conference

    Yoshihiko Akazawa*, Takaaki Kondo*, Naotaka Iwata

    International Workshop on Nitride Semiconductors 2018  ( Kanazawa, Japan )   2018.11  "Materials Science and Advanced Electronics Created by Singularity", MEXT-KAKENHI on Innovative Areas, FY2016-2020 and The Japanese Association for Crystal Growth

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    Effect of inductively coupled plasma reactive ion etching on performances of p-GaN gate AlGaN/GaN HEMTs

  • レーザを用いた局所p-GaN オーミック電極形成法の開発 International conference

    川﨑輝尚 住友重機械*, 黒瀬範子 立命館大学*, 松本晃太*, 岩田　直高, 青柳克信 立命館大学*

    第79回応用物理学会秋季学術講演会  ( 名古屋国際会議場 )   2018.9  応用物理学会

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    レーザを用いた局所p-GaN オーミック電極形成法の開発

  • A new laser induced local material engineering to convert from n-type to p-type nitride semiconductor to fabricate high power vertical AlGaN/GaN devices on Si substrate International conference

    Yoshinobu Aoyagi 立命館大学*, Noriko Kurose 立命館大学*, 松本滉太 電子デバイス*, 岩田　直高, 神谷　格

    22nd Advanced Materials 2018  ( 東京 )   2018.9 

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    レーザーを用いた GaN のドーピング活性化法を用いた縦型素子作製について

  • 選択ドライエッチングがp型GaNゲートAlGaN/GaNGaNGaN高電子移動度トランジスタの特性へ及ぼす影響 International conference

    近藤孝明*, 赤澤良彦*, 岩田　直高

    第79回応用物理学会秋季学術講演会  ( 名古屋国際会議場 )   2018.9  応用物理学会

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    選択ドライエッチングがp型GaNゲートAlGaN/GaNGaNGaN高電子移動度トランジスタの特性へ及ぼす影響

  • Mgイオン注入GaNのフラッシュランプアニールによる活性化 International conference

    大森雅登 名大未来研*, 山田隆泰 SCREENセミコンダクターソリューションズ*, 谷村英昭 SCREENセミコンダクターソリューションズ*, 加藤慎一 SCREENセミコンダクターソリューションズ*, 岩田　直高, 塩崎宏司 名大未来研*

    第79回応用物理学会秋季学術講演会  ( 名古屋国際会議場 )   2018.9  応用物理学会

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    Mgイオン注入GaNのフラッシュランプアニールによる活性化

  • p型GaNゲートを用いたノーマリオフ動作AlGaN/GaN高電子移動度トランジスタ International conference

    赤澤良彦*, 近藤孝明*, 吉川慎也*, 岩田　直高, 榊裕之*

    第65回春季応用物理学会学術講演会  ( 早稲田大学西早稲田キャンパス・ベルサール高田馬場 )   2018.3  応用物理学会

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  • 1対の電子チャネルと正孔チャネルを内蔵したAlGaAs/GaAs/AlGaAsダブルヘテロ構造における特性評価 International conference

    大保嵩博*, 櫛田知義 ＊*, テウク モハマド ロフィ, 岩田　直高

    第65回春季応用物理学会学術講演会  ( 早稲田大学西早稲田キャンパス・ベルサール高田馬場 )   2018.3  応用物理学会

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  • （招待）Suppress surface recombination by introducing metal cations into AlOx Invited International conference

    リ　ヒュンジュ, Fumiya Nishimura*, Takefumi Kamioka, Haruhiko Yoshida*, Naotaka Iwata, Yoshio Ohshita

    次世代シリコン太陽電池分科会第7回研究会  ( 東京工業大学　大岡山キャンパス　蔵前会館 )   2017.10  学振175委員会

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  • MgドープGaNへのレーザー照射による局所活性化と結晶性のその場観測 International conference

    松本滉太*, 黒瀬範子 ＊*, 山田　郁彦, 神谷　格, 青柳克信 ＊*, 岩田　直高

    IEEE Metro Area Workshop in Nagoya  ( 中京大学 / Chukyo University )   2017.10  IEEE 名古屋支部 / IEEE Nagoya Section

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  • Charge-Controllable Mg-Doped AlOx Passivation Layers for p- and n-Type Silicon International conference

    リ　ヒュンジュ, Takefumi Kamioka, Naotaka Iwata, Yoshio Ohshita, F. Nishimura, H. Yoshida*

    33rd European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC 2017)  ( RAI Convention & Exhibition Centre, Amsterdam, The Netherlands )   2017.9  WIP

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  • 放射光XRD・HAXPESによるAl/Ti/AlGaNの界面反応層の結晶構造及び化学結合状態評価 International conference

    安野聡 **, 小金澤智之 **, 鈴木貴之*, 岩田　直高

    第78回秋季応用物理学会学術講演会  ( 福岡国際会議場・国際センター・福岡サンパレス )   2017.9  応用物理学会

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  • MgドープGaNのレーザー誘起による活性化とその局所制御 International conference

    松本滉大*, 黒瀬範子 **, 下野貴史*, 岩田　直高, 山田　郁彦, 神谷　格, 青柳克信 **

    第78回秋季応用物理学会学術講演会  ( 福岡国際会議場・国際センター・福岡サンパレス )   2017.9  応用物理学会

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  • Carrier Transportation at Novel Silver Paste Contact International conference

    Yoshio Ohshita, Takefumi Kamioka, Satoshi Kameyama*, Kazuo Muramatsu, Aki Tanaka*, Naotaka Iwata, Kyotaro Nakamura, Atsushi Ogura*

    44th IEEE Photovoltaic Specialists Conference (44th IEEE PVSC)  ( Washington Marriott Wardman Park, Washington DC, USA )   2017.6  44th IEEE PVSC

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  • HCl表面処理とプラズマ励起原子層堆積 SiNx膜による AlGaN/GaN HEMTの表面安定化 International conference

    鈴木貴之*, 土屋晃祐*, 大保崇博*, 赤澤良彦*, 下野貴史*, 松本滉太*, 江口卓也*, 岩田　直高

    第64回応用物理学会春季学術講演会  ( パシフィコ横浜 )   2017.3  応用物理学会

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  • Charge-Controllable Mg-Doped AlOx for the Passivation of High Efficiency Silicon Solar Cells International conference

    リ　ヒュンジュ, Fumiya Nishimura, Haruhiko Yoshida*, Takefumi Kamioka, Naotaka Iwata, Kyotaro Nakamura*, Yoshio Ohshita

    Global Photovoltaic Conference 2017 (GPVC2017)  ( Kimdaejung Convention Center, Gwangju, Korea )   2017.3  Korea Photovoltaic Society

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  • Nano-Engineered Surface Passivation for Advanced Silicon Solar Cells International conference

    リ　ヒュンジュ, Fumiya Nishimura*, Takefumi Kamioka, Dongyan Zhang, Haruhiko Yoshida*, Naotaka Iwata, Yoshio Ohshita

    豊田工業大学スマートエネルギー技術研究センター第8回／グリーン電子素子・材料研究センター第2回合同シンポジウム  ( 豊田工業大学　愛知県名古屋市 )   2016.11  豊田工業大学

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  • Novel silver paste to n- and p-layers for fabricating high efficiency crystalline Si solar cells International conference

    Takefumi Kamioka, Tetsu Takahashi, Kazuo Muramatsu, Aki Tanaka*, Naotaka Iwata, Kyotaro Nakamura, Atsushi Ogura*, Yoshio Ohshita

    The 26th Photovoltaic Science and Engineering Conference (PVSEC-26)   ( Marina Bay Sands, Sands Expo and Convention Centre, Singapore )   2016.10  Solar Energy Research Institute of Singapore (SERIS)

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  • Excellent Surface Passivation of Crystalline Silicon by AlxMg1-xOy and Its Tunable Interface Properties International conference

    リ　ヒュンジュ, Fumiya Nishimura*, Takefumi Kamioka, Dongyan Zhang, Haruhiko Yoshida*, Naotaka Iwata, Yoshio Ohshita

    The 26th Photovoltaic Science and Engineering Conference (PVSEC-26)   ( Marina Bay Sands, Sands Expo and Convention Centre, Singapore )   2016.10  Solar Energy Research Institute of Singapore (SERIS)

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  • プラズマ励起原子層堆積プラズマ励起原子層堆積保護膜によるAlGaN/GaN HEMTの表面安定化 International conference

    鈴木貴之*, 山田富明*, 河合亮輔*, 川口翔平*, 張東岩*, 岩田　直高

    第77回応用物理学会秋季学術講演会  ( 朱鷺メッセ (新潟県新潟市) )   2016.9  応用物理学会

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  • (Invited) Dielectric Oxide Nanoengineering and Its Impact on the Surface Passivation and Interface Properties of Crystalline Silicon Invited International conference

    リ　ヒュンジュ, Naotaka Iwata, Atsushi Ogura, Haruhiko Yoshida, Toyohiro Chikyow*, Yoshio Ohshita

    The Energy Materials and Nanotechnology (EMN) Meeting on Surface and Interface 2016  ( The Royale Chulan Hotel Kuala Lumpur, Kuala Lumpur, Malaysia )   2016.9  EMN Meeting Organizing Committee

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  • Doped Dielectric Nanolayers for Advanced Surface Passivation of Silicon Solar Cells International conference

    リ　ヒュンジュ, Fumiya Nishimura*, Takefumi Kamioka, Dongyan Zhang, Haruhiko Yoshida*, Naotaka Iwata, Yoshio Ohshita

    The 26th Workshop on Crystalline Silicon Solar Cells and Modules: Materials and Processes  ( The Lodge at Vail, Colorado, USA )   2016.8  NREL

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  • Atomic Layer Deposition of AlxMg1-xOy Nanolayers and Their Excellent Surface Passivation for Crystalline Silicon Solar Cells International conference

    リ　ヒュンジュ, Takefumi Kamioka, Dongyan Zhang*, Naotaka Iwata, Yoshio Ohshita

    The 18th International Conference on Crystal Growth and Epitaxy (ICCGE-18)   ( Nagoya Congress Center, Nagoya, Japan )   2016.8  Science Council of Japan (SCJ),JACG(the Japanese Association for Crystal Growth) ,The Japan Society of Applied Physics (JSAP)

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  • Realization of Conductive AlN Epitaxial Layer on Si Substrate using Spontaneously Formed Nano-Size Via-Holes for Vertical AlGaN High Power FET International conference

    Noriko Kurose 立命館大学*, Kota Ozeki 立命館大学*, Tsutomu Araki 立命館大学*, Itaru Kamiya, Naotaka Iwata, Yoshinobu Aoyagi 立命館大学*

    The 43rd International Symposium on Compound Semiconductors (ISCS)  ( Toyama Japan )   2016.6 

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    Conductive AlN layer grown on a Si substrate using MOCVD has been realized by the spontaneously formed nano-size via-holes. The layer has been applied for the preparation of vertical AlGaN FETs.

  • Excellent Surface Passivation of Crystalline Silicon by Ternary AlxMg1-xOy Thin Films International conference

    リ　ヒュンジュ, Takefumi Kamioka, Dongyan Zhang*, Naotaka Iwata, Yoshio Ohshita

    43th IEEE Photovoltaic Specialists Conference (43rd IEEE PVSC)  ( Oregon Convention Center , Portland, OR, USA )   2016.6  43rd IEEE PVSC

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  • ALD AlxMg1-xOy Surface Passivation for Next Generation Silicon Solar Cells International conference

    リ　ヒュンジュ, Takefumi Kamioka, Dongyan Zhang*, 岩Yoshio Ohshita

    第13回次世代の太陽光発電システムシンポジウム  ( アオーレ長岡　新潟県長岡市 )   2016.5  日本学術振興会産学協力研究委員会第１７５委員会

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  • Excellent Surface Passivation of Crystalline Silicon by Atomic Layer Deposition AlxMg1-xOy Thin Films International conference

    リ　ヒュンジュ, 神岡　武文, チョウ　トウエン, 岩田　直高, 大下　祥雄

    第63回応用物理学会春季学術講演会  ( 東京工業大学　大岡山キャンパス )   2016.3  応用物理学会

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    Excellent Surface Passivation of Crystalline Silicon by Atomic Layer Deposition AlxMg1-xOy Thin Films

  • 赤外用三角障壁フォトトランジスタの暗電流低減と室温動作 International conference

    杉村和哉 電子デバイス*, 大森　雅登, 野田武司 物材研*, Vitushinskiy Pavel 電子デバイス*, 岩田　直高, 榊裕之 学長*

    第76回応用物理学会秋季学術講演会  ( 名古屋国際会議場 )   2015.9  応用物理学会

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    赤外用三角障壁フォトトランジスタの暗電流低減と室温動作

  • The Current Conduction Mechanism of Novel Silver Thick Film Electrode International conference

    高橋哲 ナミックス(株)*, 立花福久 産総研福島*, 神岡　武文, 岩田　直高, 大下　祥雄

    31st European Photovoltaic Solar Energy Conference and Exhibition  ( Hamburg, Germany )   2015.9  WIP GmbH & Co-KG

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    The Current Conduction Mechanism of Novel Silver Thick Film Electrode

  • InP(100)基板上におけるInAs/InAlGaAs量子ロッド構造の形成 International conference

    大森　雅登, 野田武司 物材研*, 小嶋友也 ナノ電子*, 杉村和哉 電子デバイス*, Vitushinskiy Pavel 電子デバイス*, 岩田　直高, 榊裕之 学長*

    第76回応用物理学会秋季学術講演会  ( 名古屋国際会議場 )   2015.9  応用物理学会

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    InP(100)基板上におけるInAs/InAlGaAs量子ロッド構造の形成

  • AlGaAs/InGaAs HEMTs Passivated with Atomic Layer Deposited SiO2 using Aminosilane Precursors International conference

    鈴木貴之 電子デバイス*, 滝川陽介 電子デバイス*, 岩田　直高, チョウ　トウエン, 大下　祥雄

    The 2015 International Meeting for Future of Electron Devices, Kansai (IMFEDK2015)  ( Kyoto, Japan )   2015.6  IEEE

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    AlGaAs/InGaAs HEMTs Passivated with Atomic Layer Deposited SiO2 using Aminosilane Precursors

  • 三角障壁フォトトランジスタによる高感度赤外光検出 International conference

    大森　雅登, 杉村和哉*, 小嶋友也*, 加戸作成*, 野田武司*, パベル　ヴィトゥシンスキー, 岩田　直高, 榊　裕之

    第62回応用物理学会春季学術講演会  ( 東海大学　湘南キャンパス )   2015.3  応用物理学会

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  • ビスエチルメチルアミノシランを用いた原子層堆積SiO2保護膜を有するAlGaAs/InGaAs HEMTの特性 International conference

    鈴木貴之*, 滝川陽介*, 張東岩*, 内藤志麻子*, 岩田　直高

    第62回応用物理学会春季学術講演会  ( 東海大学　湘南キャンパス )   2015.3  応用物理学会

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    未結合手の終端に優れたプラズマ励起原子層堆積(PEALD)法によってHEMT表面に2種類の有機原料を用いてSiO2を堆積した．それらがトランジスタ特性に与える影響を評価した。

  • 原料断続供給法を用いたSiO2薄膜マスク付Si 基板上へのGaAs 成長における初期結晶形状の評価 International conference

    邢 林 宮崎大学*, 横山 祐貴 宮崎大学*, 杉村 和哉*, 滝川 陽介*, 鈴木 秀俊 宮崎大学*, 岩田　直高, 前田 幸治 宮崎大学*

    2014年(平成26年度)応用物理学会九州支部学術講演会  ( 大分大学工学部（大分市旦野原７００） )   2014.12  応用物理学会

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    開口部に均一な結晶を得るには、SiO2及びSi上での原料の拡散の制御が必要である。我々は、表面拡散の制御手法として原料断続供給法に注目し、高品質なGaAsの成長に取り込んでいる。本研究では、原料断続供給法を用いて様々な形状に開口したSiO2薄膜上にGaAsの結晶成長を行い、マスク部及びその開口部近傍でのGaAs結晶の成長初期の形状観察を行うことによって、SiO2 及びSi 上での原料拡散のメカニズムを理解することを目的とした。

  • EVALUATION OF INTERFACE RECOMBINATION INDUCED BY FIRE-THROUGH AG PAST FOR HIGH OPEN CIRCUIT VOLTAGE International conference

    青木真理 半導体*, 大下　祥雄, 高橋哲 ナミックス(株)*, 立花福久 半導体*, I. Suminta 半導体*, 滝川陽介 電子デバイス*, 岩田　直高

    29th European Photovoltaic Solar Energy Conference and Exhibition  ( Amsterdam, The Netherlands )   2014.9  WIP

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    EVALUATION OF INTERFACE RECOMBINATION INDUCED BY FIRE-THROUGH AG PAST FOR HIGH OPEN CIRCUIT VOLTAGE

  • EVALUATION OF INTERFACE RECOMBINATION INDUCED BY FIRE-THROUGH AG PAST FOR HIGH OPEN CIRCUIT VOLTAGE International conference

    青木真理 半導体*, 大下　祥雄, 高橋哲 ナミックス(株)*, 立花福久 半導体*, I. Suminta 半導体*, 滝川陽介 電子デバイス*, 岩田　直高

    29th European Photovoltaic Solar Energy Conference and Exhibition  ( Amsterdam, The Netherlands )   2014.9  WIP

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    EVALUATION OF INTERFACE RECOMBINATION INDUCED BY FIRE-THROUGH AG PAST FOR HIGH OPEN CIRCUIT VOLTAGE

  • Novel vertical AlGaN deep ultra violet photo-detector on n+Si substrate using spontaneous via holes growth technique International conference

    Kota Ozeki Ritsumeikan University*, Noriko Kurose Ritsumeikan University*, Naotaka Iwata, Kentaro Shibano Ritsumeikan University*, Tsutomu Araki Ritsumeikan University*, Itaru Kamiya, Yoshinobu Aoyagi Ritsumeikan University*

    The 2014 International Conference on Solid State Devices and Materials  ( Tsukuba International Congress Center )   2014.9  THE JAPAN SOCIETY OF APPLIED PHYSICS

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    Vertical AlGaN deep ultra violet (DUV) photo-detector has been successfully fabricated on n+Si substrate using spontaneous via holes growth technique. The spontaneous via holes make the insulating AlN buffer layer to be conductive, which is indispensable to grow AlGaN epitaxial layer, and makes possible the direct current flow from p electrode to n+Si substrate without any trench etching to form n-contact. This vertical device is easily enlarged to realize large area solar-blind photo-detector which is necessary for many applications for sensing contamination of water, biological material and so on under the sunshine.

  • 化合物半導体ヘテロ接合デバイスの研究開発　　－移動体通信端末と基地局への適用－ Invited International conference

    岩田　直高

    宮崎大学平成25年度ＩＲ推進機構講演会  ( 宮崎大学　木花キャンパス　総合研究棟　プレゼンテーションルーム )   2013.9  宮崎大学　ＩＲ推進機構

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    Presentation type：Oral presentation (invited, special)  

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Awards

  • 平成16年度　電気通信大学 同窓会賞

    2004.4   電気通信大学同窓会社団法人目黒会   移動体端末用高出力ヘテロ接合FETの開発

    岩田　直高

  • 文部科学大臣賞 第29回研究功績者表彰

    2003.4   文部科学省   携帯電話端末用ヘテロ接合FETの研究

    岩田　直高

  • 第34回市村産業賞 功績賞

    2002.4   財団法人新技術開発財団   携帯電話端末用ヘテロ接合FETの開発と実用化

    岩田　直高

Grant-in-Aid for Scientific Research

Social Activities

  • Consortium for GaN Research and Applications

    Role(s)： Organizing member

    2019.10

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    Type：TV or radio program