窒化物半導体混晶のバルク準位評価とナノ構造表面制御

• Project Area: Optoelectronics Frontier by Nitride Semiconductor -Ultimate Utilization of Nitride Semiconductor Material Potential-
• Project/Area Number: 21016001
• Research Category: Grant-in-Aid for Scientific Research on Priority Areas
• Allocation Type: Single-year Grants
• Review Section: Science and Engineering
• Research Institution: Hokkaido University
• Principal Investigator: 橋詰 保 北海道大学, 量子集積エレクトロニクス研究センター, 教授 (80149898)
• Co-Investigator(Kenkyū-buntansha): 佐藤 威友 北海道大学, 量子集積エレクトロニクス研究センター, 准教授 (50343009) ; 古賀 裕明 北海道大学, 量子集積エレクトロニクス研究センター, 助教 (80519413)
• Project Period (FY): 2009 – 2010
• Project Status: Completed (Fiscal Year 2010)
• Budget Amount: ¥7,000,000 (Direct Cost: ¥7,000,000); Fiscal Year 2010: ¥3,500,000 (Direct Cost: ¥3,500,000); Fiscal Year 2009: ¥3,500,000 (Direct Cost: ¥3,500,000)
• Keywords: AlGaN / 有機金属気相成長 / DLTS / 深い準位 / 表面準位 / フェルミ準位安定化エネルギー / 電気化学酸化 / AlInN / 表面フェルミ準位 / バンド不連続量

Research Abstract

AlGaNおよびAlInGaNのバルク欠陥準位と表面・端面における表面電子準位を系統的に評価し、その理解を基盤として、短波長光学素子の高効率化・動作安定化のための電子準位制御法を構築することを目的として研究を展開した。本年度の主な成果を以下にまとめる。
1)減圧有機金属気相法により成長したn-AlGaN(膜厚:1μm、Al組成:25、37、60%)の深い準位を評価し、伝導帯下端より1eV以上のエネルギーを持つ電子準位を検出した。支配的準位エネルギーのAl組成依存性は、フェルミ準位安定化エネルギーの計算値に良く追従することを明らかにし、逆位置欠陥と空孔欠陥ペアの複合型欠陥が深い準位の成因である可能性を指摘した。
2)原子層堆積により形成したAl_2O_3/AlGaN/GaN構造に、詳細な計算解析とバンドギャップ以下のエネルギーを持つ光支援測定法を適用し、その容量-電圧特性を評価した。その結果、Al_2O_3/AlGaN界面には1x10^<12>cm^<-2>eV^<-1>以上の密度を持つ電子準位が存在することを初めて明らかにした。
3)AlGaN表面に電気化学酸化法を適用し、平坦で均一性の高い母体酸化膜を形成することができた。形成した酸化膜の組成は母体AlGaNの組成とほぼ同等であることが分かり、この手法によりAlGaNの表面準位密度を低減できることを明らかにした。また、プロセスによりダメージを受けたGaN表面の欠陥層除去にも適用可能であることがわかった。

Research Products

• [Journal Article] Variation of Chemical and Photoluminescence Properties of Mg-Doped GaN Caused by High-Temperature Process (2011)
  • Author(s): E.Ogawa, T.Hashizune
  • Journal Title: Jpn.J.Appl.Phys Volume: 50
  • Peer Reviewed
• [Journal Article] Capacitance-voltage characteristics of Al_2O_3/AlGaN/GaN structures and state density distribution at Al_2O_3/AlGaN interface (2011)
  • Author(s): C.Mizue, Y.Hori, M.Miczek, T.Hashizume
  • Journal Title: Jpn.J.Appl.Phys Volume: 50
  • Peer Reviewed
• [Journal Article] Formation of recessed-oxide gate for normally-off AlGaN/GaN HEMTs using a selective electrochemical oxidation (2011)
  • Author(s): N.Harada, Y.Hori, N.Azumaishi, K.Ohi, T.Hashizume
  • Journal Title: Appl.Phys.Express Volume: 4
  • Peer Reviewed
• [Journal Article] Small valence-band offset of In0.17Al0.83N/GaN heterostructure grown by metal-organic vapor phase epitaxy (2010)
  • Author(s): M.Akazawa, T.Matsuyama, T.Hashizume, M.Hiroki, S.Yamahata, N.Shigekawa
  • Journal Title: Appl.Phys.Lett. Volume: 96
  • Peer Reviewed
• [Journal Article] Process conditions for improvement of electrical properties of Al_2O_3/n-GaN structures prepared by atomic layer deposition (2010)
  • Author(s): Y.Hori, C.Mizue, T.Hashizume
  • Journal Title: Jpn.J.Appl.Phys Volume: 49
  • Peer Reviewed
• [Journal Article] Deep electronic levels of Al_xGa_<1-x>N with a wide range of Al composition grown by metal-organic vapor phase epitaxy (2010)
  • Author(s): K.Ooyama, K.Sugawara, S.Okuzaki, H.Taketomi, H.Miyake, K.Hiramatsu, T.Hashizume
  • Journal Title: Jpn.J.Appl.Phys Volume: 49
  • Peer Reviewed
• [Journal Article] Trap states in AlGaN/GaN metal-oxide-semiconductor structures with Al_2O_3 prepared by atomic layer deposition (2010)
  • Author(s): D.Gregusova, R.Stoklas, C.Mizue, Y.Hori, J.Novak, T.Hashizume, P.Kordos
  • Journal Title: J.Appl.Phys. Volume: 107
  • Peer Reviewed
• [Journal Article] Variation of surface potentials of Si-doped Al_xGa_<1-x>N(0<x<0.87)grown on AlN/sapphire template by metal-organic vapor phase epitaxy (2010)
  • Author(s): T.Kubo, H.Taketomi, H.Miyake, K.Hiramatsu, T.Hashizume
  • Journal Title: Appl.Phys.Express 3
  • Peer Reviewed
• [Journal Article] Near-midgap deep levels in Al_<0.26>Ga_<0.74>N grown by metal-organic chemical vapord eposition (2009)
  • Author(s): K.Sugawara, J.Kotani, T.Hashizume
  • Journal Title: Appl.Phys.Lett. 94
  • Peer Reviewed
• [Journal Article] Simulations of C-V-T Behavior of Metal/Insulator/AlGaN and Metal/Insulator/AlGaN/GaN Structures (2009)
  • Author(s): M.Miczek, B.Adamowicz, C.Mizue, T.Hashizume
  • Journal Title: Jpn.J.Appl.Phys. 48
  • Peer Reviewed
• [Journal Article] Drain Current Stability and Controllability of Threshold Voltage and Subthreshold Current in a Multi-Mesa-Channel AlGaN/GaN High Electron Mobility Transistor (2009)
  • Author(s): K.Ohi, T.Hashizume
  • Journal Title: Jpn.J.Appl.Phys. 48
  • NAID: 40016704629
  • Peer Reviewed
• [Journal Article] Surface control of GaN alloys for photonic and electronic devices (2009)
  • Author(s): T.Hashizume, N.Shiozaki, K.Ohi
  • Journal Title: Proc.of SPIE, Gallium Nitride Materials and Devices IV 7216
  • Peer Reviewed
• [Journal Article] GaNおよびAlGaNの深い電子準位-電気的評価結果を中心として-(解説) (2009)
  • Author(s): 橋詰保
  • Journal Title: 日本結晶成長学会誌 36
  • Peer Reviewed
• [Presentation] MOVPE法によるAlGaN中の深い準位 (2010)
  • Author(s): 橋詰保
  • Organizer: 応用物理学会シンポジウム(ワイドギャップ窒化物AlGaNの結晶評価と深紫外光デバイス応用)
  • Place of Presentation: 長崎(Invited 招待講演)
  • Year and Date: 2010-09-16
• [Presentation] 窒化物半導体の表面・界面制御とパワートランジスタ展開 (2010)
  • Author(s): 橋詰保
  • Organizer: 日本学術振興会アモルファス・ナノ材料第147委員会第108回研究会
  • Place of Presentation: 東京(Invited 招待講演)
  • Year and Date: 2010-07-09
• [Presentation] AlGaNの深い電子準位と表面ポテンシャル (2010)
  • Author(s): 橋詰保
  • Organizer: 応用物理学会応用電子物性分科会研究会
  • Place of Presentation: 大阪(Invited 招待講演)
  • Year and Date: 2010-05-21
• [Presentation] 窒化物半導体の特徴とデバイス展開(Invited) (2010)
  • Author(s): 橋詰保
  • Organizer: 第27回無機材料に関する最近の研究成果発表会-材料研究の最前線から-
  • Place of Presentation: 東京
  • Year and Date: 2010-01-25
• [Presentation] Current controllability and stability of multi-mesa-channel AlGaN/GaN HEMTs (2010)
  • Author(s): T.Hashizume, K.Ohi
  • Organizer: 2010 International Meeting for Future of Electron Devices, Kansai (IMFEDK)
  • Place of Presentation: Osaka(Invited 招待講演)
• [Presentation] Interface control technologies of GaN-based MOS structures for high-efficiency power switching transistors (2010)
  • Author(s): T.Hashizume, Y.Hori, C.Mizue
  • Organizer: Workshop on Dielectrics in Microellectronics (WoDiM 2010)
  • Place of Presentation: Bratislava, Slovak(Invited 招待講演)
• [Presentation] Interface state properties of Al_2O_3/n-GaN prepared by atomic layer deposition (2010)
  • Author(s): Y.Hori, C.Mizue, T.Hashizume
  • Organizer: International Meeting for Future of Electron Devices, Kansai (IMFEDK)
  • Place of Presentation: Osaka
• [Presentation] C-V characterization of ALD-Al_2O_3 insulated gates on AlGaN/GaN structure (2010)
  • Author(s): C.Mizue, T.Hashizume
  • Organizer: Workshop on Dielectrics in Microellectronics (WoDiM 2010)
  • Place of Presentation: Bratislava, Slovak
• [Presentation] A recessed oxide gate structure for threshold voltage control in AlGaN/GaN HEMTs by electrochemical process (2010)
  • Author(s): N.Harada, T.Hashizume
  • Organizer: 2010 International Workshop on Nitride Semiconductors (IWN-2010)
  • Place of Presentation: Tampa, USA
• [Presentation] Effects of Mg-doping density and high-temperature annealing on deep levels in Mg-doped GaN (2010)
  • Author(s): E.Ogawa, T.Hashizume
  • Organizer: 2010 International Workshop on Nitride Semiconductors (IWN-2010)
  • Place of Presentation: Tampa, USA
• [Presentation] Current Controllability and Stability in Multi-Mesa-Channel AlGaN/GaN HEMT (2010)
  • Author(s): K.Ohi, T.Hashizume
  • Organizer: 2010 International Workshop on Nitride Semiconductors (IWN-2010)
  • Place of Presentation: Tampa, USA
• [Presentation] Effects of fabrication processes on electrical properties of Al_2O_3/n-GaN structures prepared by atomic layer deposition (2010)
  • Author(s): Y.Hori, T.Hashizume
  • Organizer: 2010 International Workshop on Nitride Semiconductors (IWN-2010)
  • Place of Presentation: Tampa, USA
• [Presentation] Trapping Region Extension at the Gate-Drain Opening of AlGaN/GaN Heterojunction Field-Effect Transistors Subjected to On-State Stress (2010)
  • Author(s): C.-Y.Hu, T.Hashizume, K.Ohi, M.Tajima
  • Organizer: 2010 International Workshop on Nitride Semiconductors (IWN-2010)
  • Place of Presentation: Tampa, USA
• [Presentation] Deep level characterization of MOVPE-grown AlGaN with high Al compositions (2010)
  • Author(s): S.Okuzaki, K.Sugawara, H.Taketomi, H.Miyake, K.Hiramatsu, T.Hashizume
  • Organizer: 2010 International Conference on Solid-State Devices and Materials (SSDM2010)
  • Place of Presentation: Tokyo
• [Presentation] Effects of plasma processing on surface properties of GaN and AlGaN(Invited) (2010)
  • Author(s): 橋詰保
  • Organizer: 2^<nd> International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials(ISPlasma-2010)
  • Place of Presentation: Nagoya, Japan
• [Presentation] Characterization and control of GaN and AlGaN surfaces for high-performance GaN-based transistors(Invited) (2009)
  • Author(s): 橋詰保
  • Organizer: Huang Kun Forum
  • Place of Presentation: Chinese Academy of Science, Beijin, China
  • Year and Date: 2009-11-06
• [Presentation] 窒化物半導体のMIS界面電子準位(Invited) (2009)
  • Author(s): 橋詰保
  • Organizer: 日本学術振興会第154委員会・第162委員会合同研究会
  • Place of Presentation: 東京
  • Year and Date: 2009-10-26
• [Presentation] Effects of high-temperature anneal on surface properties of Mg-doped GaN (2009)
  • Author(s): E.Ogawa, T.Hashizurne
  • Organizer: 2009 International Meeting for Future of Electron Devices, Kansai(IMFEDK)
  • Place of Presentation: Osaka, Japan
• [Presentation] Interface characterization of Al2O3/n-GaN structure prepared by atomic layer deposition (2009)
  • Author(s): K.Ooyama, C.Mizue, Y.Hori, T.Hashizume
  • Organizer: 2009 Asia-Pacific Workshop on Fundamental and Application of Advanced Semiconductor Devices(AWAD 2009)
  • Place of Presentation: Busan, Korea
• [Presentation] Electrochemical oxidation of GaN for surface control of GaN-based device structures (2009)
  • Author(s): N.Harada, N.Shiozaki, T.Hashizume
  • Organizer: 2009 International Conference on Solid-State Devices and Materials(SSDM2009)
  • Place of Presentation: Sendai, Japan
• [Presentation] Chemical and electronic properties of ALD-Al_2O_3/AlGaN interfaces (2009)
  • Author(s): Y.Hori, C.Mizue, K.Ooyama, M.Miczek, T.Hashizume
  • Organizer: 2009 International Conference on Solid-State Devices and Materials(SSDM2009)
  • Place of Presentation: Sendai, Japan
• [Presentation] Chemical and Electronic Properties of MOVPE-grown Al_xGa_<1-x>N Surfaces(0.25<x<0.68) (2009)
  • Author(s): T.Kubo, K.Sugawara, H.Taketomi, H.Miyake, K.Hiramatsu, T.Hashizume
  • Organizer: 8th International Conference on Nitride Semiconductors(ICNS-8)
  • Place of Presentation: Jeju, Korea
• [Presentation] Correlation between surface leakage current and operation degradation of AlGaN/GaN HEMTs (2009)
  • Author(s): M.Tajima, T.Hashizume
  • Organizer: 8th International Conference on Nitride Semiconductors(ICNS-8)
  • Place of Presentation: Jeju, Korea
• [Presentation] Characterization of interface electronic states in ALD-Al_2O_3/AlGaN/GaN structures (2009)
  • Author(s): C.Mizue, Y.Hori, M.Miczek, T.Hashizume
  • Organizer: 8th International Conference on Nitride Semiconductors(ICNS-8)
  • Place of Presentation: Jeju, Korea
• [Presentation] Mg accumulation and defect formation at p-GaN surfaces caused by a high-temperature annealing (2009)
  • Author(s): E.Ogawa, T.Hashizume
  • Organizer: 8th International Conference on Nitride Semiconductors(ICNS-8)
  • Place of Presentation: Jeju, Korea
• [Presentation] Multi-Mesa-Channel Structure for Improvement of Gate Controllability and Current Stability in AlGaN/GaN HEMTs (2009)
  • Author(s): K.Ohi, T.Hashizume
  • Organizer: 8th International Conference on Nitride Semiconductors(ICNS-8)
  • Place of Presentation: Jeju, Korea
• [Presentation] Characterization of Schottky interface properties and deep levels of Al_xGa_<1-x>N(0.25<x<0.68)grown by MOVPE (2009)
  • Author(s): K.Sugawara, T.Kubo, H.Taketomi, H.Miyake, K.Hiramatsu, T.Hashizume
  • Organizer: 8th International Conference on Nitride Semiconductors(ICNS-8)
  • Place of Presentation: Jeju, Korea
• [Remarks] 北海道大学学術成果コレクション
  • URL: http://eprints.lib.hokudai.ac.jp/dspace/
• [Remarks] 北海道大学量子集積エレクトロニクス研究センター
  • URL: http://www.rciqe.hokudai.ac.jp
• [Remarks] 北海道大学学術成果コレクション
  • URL: http://eprints.lib.hokudai.ac.jp/dspace/
• [Remarks] 北海道大学量子集積エレクトロニクス研究センター
  • URL: http://www.rciqe.hokudai.co.jp