研究テーマ

最新技術の構造およびプロセスを利用したＧａＮ系トランジスタの電流コラプスの抑制

研究概要

地球温暖化対策として、温室効果ガスの削減が世界各地で行われています。温暖化対策として、電力消費を抑える革新的な技術創出を目指していかねばなりません。供給された電力を必要な形式の電力に変換・制御するためのパワーエレクトロニクス用半導体素子には主にシリコンＳｉを材料としたトランジスタ・ダイオードが用いられていますが、近年はワイドギャップ半導体の窒化ガリウムＧａＮに注目が集まっています。ＧａＮはＳｉよりも１０００分の１近くオン抵抗を低減することが可能なために熱損失を減らし電力消費を抑えることができます。我々の目標は、ＧａＮ系デバイスを基調とした高効率・高安定なパワーデバイスを実用化することによって、超低消費電力社会を実現することです。

研究業績

原著論文

• AlGaN/GaN MIS-HEMTs with VTH = +5 V and IDmax > 400 mA/mm achieved using recessed-gate with regrown ultrathin AlGaN barrier Joel.T.Asubar, Shinsaku Kawabata, Hirokuni Tokuda, Akio Yamamoto, and Masaaki Kuzuhara
  IEEE Electron Device Letters (under revision)
• On the presence of Ga2O sub-oxide in high-pressure water vapor annealed AlGaN surface by combined XPS and first-principles methods Mary Clare S. Escaño, Joel T. Asubar, Zenji Yatabe, Melanie Y. David, Hirokuni,Tokuda, Yukiharu Uraoka, Masaaki Kuzuhara, and Masahiko Tani
  Applied Surface Science (under revision)
• Spatial distribution of substitutional Mn-As clusters in ferromagnetic (Zn,Sn,Mn)As2 thin films revealed by image reconstruction of atom probe tomography (EDITOR’S PICK) H. Oomae, H. Shinoda, J. T. Asubar, K. Sato, H. Toyota, K. Mayama, B. Medhiyev, and N. Uchitomi
  Journal of Applied Physics 125 (2019) 073902
• Zenji Yatabe, Shinya Inoue, J.T.Asubar, and Seiya Kasai
  Analytical derivation of charge relaxation time distribution in transistor from current noise spectrum using inverse integral transformation method
  Applied Physics Express 11 031201-1-031201-4 Jun 2018
• Hirokuni Tokuda, Kosuke Suzuki, J.T.Asubar, and Masaaki Kuzuhara
  Electron concentration in highly resistive GaN substrates co-doped with Si, C, and Fe
  Japanese Journal of Applied Physics 57 071001-1-071001-4 May 2018
• Taisei Yamazaki, Joel T. Asubar, Hirokuni Tokuda, and Masaaki Kuzuhara
  Impact of rounded electrode corners on breakdown characteristics of AlGaN/GaN high-electron mobility transistors
  Applied Physics Express 11 054102-1-054102-5 Apr 2018
• Naotaka Uchitomi, Shiro Hidaka, Shin Saito, Joel T. Asubar, and Hideyuki Toyota
  Magnetic phase change in Mn-doped ZnSnAs2 thin films depending on Mn concentration
  Journal of Applied Physics 123 161566-1-161566-7 Apr 2018
• Shintaro Ohi, Taisei Yamazaki, Joel T. Asubar, Hirokuni Tokuda, and Masaaki Kuzuhara
  Correlation of AlGaN-GaN high-electron-mobility transistors electroluminescence characteristics with current collapse
  Applied Physics Express 11 024101-1-024101-14 Jan 2018
• Kouichi Hayashi, Naotaka Uchitomi, Keitaro Yamagami, Akiko Suzuki, Hayato Yoshizawa,J.T.Asubar,Naohisa Happo, Shinya Hosokawa
  Large As sublattice distortion in sphalerite ZnSnAs2 thin films revealed by x-ray fluorescence holography
  Journal of Applied Physics 119 (12), 125703 Publication date　2016/3/28
• J.T.Asubar, Y. Sakaida, S. Yoshida, Z. Yatabe, H. Tokuda, T. Hashizume, and M. Kuzuhara
  Impact of oxygen plasma treatment on the dynamic on-resistance of AlGaN/GaN high-electron-mobility transistors
  Accepted for publication in Applied Physics Express　8(11).111001(Nov2015)
• J.T.Asubar,Y. Kobayashi, K. Yoshitsugu, Z. Yatabe, H. Tokuda, M. Horita, Y. Uraoka, T. Hashizume, and M. Kuzuhara
  Current Collapse Reduction in AlGaN/GaN HEMTs by High Pressure Water Vapor Annealing
  IEEE Transactions on Electron Devices 62(8), 2423(Aug2015)
• J.T.Asubar, A. Suzuki, K. Akira, H. Tokuda, and M. Kuzuhara
  Multi-Grooved Field-Plate AlGaN/GaN HEMTs for Essentially Collapse-Free Operation without Drain Current Reduction Penalty
  submitted to International Electron Devices Meeting (IEDM).
  
• J.T.Asubar,A. Suzuki, K. Akira, H. Tokuda, and M. Kuzuhara
  Multi-Grooved Field-Plate AlGaN/GaN HEMTs for Essentially Collapse-Free Operation without Drain Current Reduction Penalty
  submitted to International Electron Devices Meeting (IEDM)
• Y. Suzuki, K. Tone,J.T.Asubar,M. Kuzuhara, and H. Tokuda
  High Drain Current and Low On-Resistance in AlGaN/GaN HEMTs with Au-Plated Ohmic Electrodes
  Proceedings of 2015 International Meeting for Future of Electron Devices Kansai (IMFEDK 2015) 52-53 (2015).
• S. Yoshida, Y. Sakaida, J.T.Asubar,H. Tokuda, and M. Kuzuhara
  Current Collapse in AlGaN/GaN HEMTs with a GaN Cap Layer
  Proceedings of 2015 International Meeting for Future of Electron Devices Kansai (IMFEDK 2015) 48-49 (2015).
• A. Sasakura,J.T.Asubar,H. Tokuda, and M. Kuzuhara
  Cu/Al/Mo/Au and Ni/Al/Mo/Au ohmic contacts for AlGaN/GaN heterostructures
  Proceedings of 2015 International Meeting for Future of Electron Devices Kansai (IMFEDK 2015) 42-43 (2015).
• A. Suzuki, K. Akira,J.T.Asubar,H. Tokuda and M. Kuzuhara
  Improved Current Collapse in AlGaN/GaN HEMTs with 3-Dimensional Field Plate Structure
  Proceedings of 2015 International Meeting for Future of Electron Devices Kansai (IMFEDK 2015) 36-37 (2015).
• S. Ohi, Y. Sakaida,J.T.Asubar,H. Tokuda, and M. Kuzuhara
  Correlation between Electroluminescence and Current Collapse in AlGaN/GaN HEMTs
  Compound Semiconductor Manufacturing Technology Technical Digest (CS MANTECH 2015), 265-268 (May 2015).
• Y.Kobayashi,J.T.Asubar,K. Yoshitsugu, H. Tokuda, M. Horita,Y. Uraoka, and M. Kuzuhara
  Suppressed Current Collapse in High Pressure Water Vapor Annealed AlGaN/GaN HEMTs
  Compound Semiconductor Manufacturing Technology Technical Digest (CS MANTECH 2015), 185-188 (May 2015).