| Project/Area Number |
09555002
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | University of Tsukuba Grant-in-Aid for Scientific Research (B)(2) |
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Principal Investigator |
HASEGAWA Fumio University of Tsukuba, Institute of Applied Physics, Professor, 物理工学系, 教授 (70143170)
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| Co-Investigator(Kenkyū-buntansha) |
USUI Akira NEC Corporation, Opto-Electronic Res.Lab., Principal researcher, 光エレクトロニクス研究所, 部長
SUEMATU Takashi University of Tsukuba, Institute of Applied Physics, Lecturer, 物理工学系, 講師 (40282339)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥9,200,000 (Direct Cost: ¥9,200,000)
Fiscal Year 1999: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1998: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥5,500,000 (Direct Cost: ¥5,500,000)
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| Keywords | GaN / bulk GaN / HVPE / GaAs substrate / free standing GaN / halide vapor phase epitaxy / ultra violet laser diode / ハライド気相成長 / 青色レーザ・ダイオード / 六方晶GaN / ナイトライド / 立方晶GaN / 青色レーザー・ダイオード / 厚膜エピタキシャル成長 |
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| Research Abstract |
A GaN substrate is desperately needed for development of practical InGaN/GaN based ultraviolet laser diodes. Purpose of this work is to obtain a free standing GaN substrate by growth of thick GaN on GaAs substrates by halide VPE.
At the beginning of the project, it was thought that cubic (zinc blende structure) GaN was practical for development of nitride based laser diodes, and growth of thick cubic GaN on GaAs(001) substrates was pursued by HVPE.Cubic phase purity of 98% for 2um thick layer and 90% for 5 um thick layer, which were the world record at that time, was obtained. An ultra violet laser diode, however, was realized in 1998on hexagonal (Wurtzite) GaN, so the subject was changed to growth of thick hexagonal GaN on GaAs (111) substrates.
The biggest problem of GaN HVPE growth on GaAs(111) was endurance of GaAs at high temperatures. It was found, however, that GaAs could stand 1000℃ growth by covering whole GaAs substrate with intermediate GaN layer grown at about 850℃. Furthermore, it was found that there was some surface flattening growth mechanism for growth of hexagonal GaN at above 1000℃.
Although a GaAs (111) substrate has polarity, GaN grown by HVPE has always Ga polarity, independently of the polarity of the substrate or the low temperature buffer layer. This is probably due to the fact that growth mechanism of HVPE is surface kinetic limited, and this is the reason why crystal quality of GaN is very high.
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