权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Fabrication of single crystalline bulk GaN substrates using GaAs as seed crystals

使用 GaAs 作为晶种制造单晶体 GaN 衬底

基本信息

批准号：
09555002
负责人：
HASEGAWA Fumio
金额：
$ 5.89万
依托单位：
University of Tsukuba Grant-in-Aid for Scientific Research (B)(2)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09555002/
关键词：
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

项目摘要

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.

开发实用的InGaN/GaN基紫外激光二极管迫切需要GaN衬底。本工作的目的是通过卤化VPE在GaAs衬底上生长厚GaN来获得独立的GaN衬底。在项目开始时，人们认为立方（锌矿结构）GaN对于氮基激光二极管的发展是可行的，并且HVPE追求在GaAs（001）衬底上生长厚立方GaN。2um厚层的立方相纯度为98%，5um厚层的立方相纯度为90%，创造了当时的世界纪录。然而，1998年在六边形（纤锌矿）氮化镓上实现了紫外激光二极管，因此该主题改为在GaAs（111）衬底上生长厚六边形氮化镓。在GaAs（111）上生长GaN HVPE的最大问题是GaAs在高温下的耐久性。然而，在850℃左右生长的中间GaN层覆盖整个GaAs衬底，GaAs可以经受1000℃的生长。此外，在1000℃以上，六方GaN的生长存在一定的表面扁平生长机制。尽管GaAs（111）衬底具有极性，但HVPE生长的GaN始终具有Ga极性，与衬底或低温缓冲层的极性无关。这可能是由于HVPE的生长机制受到表面动力学的限制，这也是GaN晶体质量非常高的原因。