利用MOCVD在r面蓝宝石上生长的a面GaN中两步AlN缓冲层的优化(英文)  

Optimization of Two-step AlN Buffer of a-plane GaN Films Grown on r-plane Sapphire by MOCVD

作　　者：何涛[1] 陈耀[1] 李辉[1] 戴隆贵[1] 王小丽[1] 徐培强[1] 王文新 陈弘[1] 

机构地区：[1]中国科学院物理研究所凝聚态国家重点实验室,北京100190

出　　处：《发光学报》2011年第4期363-367,共5页Chinese Journal of Luminescence

基　　金：Project supported by the National Natural Science Foundation of China(60890192,60877006,50872146);the Chinese Science and Technology Ministry(“863”,No.2009AA033101)~~

摘　　要：采用两步AlN缓冲层(一层低温AlN和一层高温AlN)在r面蓝宝石衬底上生长了非极性的a面GaN,并利用高分辨X射线衍射和光致荧光谱对所生长的材料进行了研究。两步AlN缓冲层在我们之前的工作中已被证明比单步高温AlN或低温GaN缓冲层更有利于减小材料各向异性和提高晶体质量,本文进一步优化了两步AlN缓冲层的结构,并得到了各向异性更小,晶体质量更好的a面GaN薄膜。分析表明,两步AlN缓冲层中的低温AlN层在减小各向异性中起着关键作用。低温AlN层能抑制了优势方向(c轴)的原子迁移,有利于劣势方向(m轴)的原子迁移,从而减小了Al原子在不同方向迁移能力的差异,并为其后的高温AlN缓冲层和GaN层提供"生长模板",以得到各向异性更小、晶体质量更好的a面GaN材料。Nonpolar（1120） a-plane GaN films with two-step AlN buffer（a low-temperature（LT） and a high-temperature（HT） AlN layers） were grown on（1102） r-plane sapphire by metalorganic chemical vapor deposition（MOCVD）.The as-grown films were investigated by high-resolution X-ray diffraction（XRD） and photoluminescence（PL）.The two-step AlN buffer has been proved to be advantageous in crystal quality compared with one-step LT-GaN or HT-AlN buffers in our early works.In this report,the thickness of the two-step buffer was further optimized,and much less anisotropic a-plane GaN films were achieved.It was found that the LT-AlN layer of the two-step buffer played a key role in reduction of anisotropy of the GaN film grown.

关 键 词：GAN 各向异性 X射线衍射 ALN 缓冲层 

分 类 号：O472[理学—半导体物理] O482.31[理学—物理]