缓冲层厚度对MOCVD法生长GaN外延薄膜性能的影响  

Influence of Buffer Layer Thickness on the Properties of an Undoped GaN Layer Grown on Sapphire Substrate by Metalorganic Chemical Vapor Deposition

作　　者：吴洁君[1] 韩修训[1] 李杰民[1] 黎大兵[1] 魏宏远[1] 康亭亭[1] 王晓晖[1] 刘祥林[1] 王占国[1] 

机构地区：[1]中国科学院半导体研究所,材料开放重点实验室北京100083

出　　处：《人工晶体学报》2005年第3期466-470,共5页Journal of Synthetic Crystals

基　　金：国家自然科学基金(No.60376013;60136020)资助

摘　　要：本文研究了低温GaN(LTGaN)缓冲层表面形貌,其随厚度的变化规律及对随后生长GaN外延膜各项性能的影响。用场发射扫描电镜(SEM)和原子力显微镜(AFM)研究LTGaN缓冲层表面形貌,发现随着厚度的增加,其表面由疏松、粗糙变得致密、平整,六角GaN小晶粒的数量减少,且取向较为一致。用X光双晶衍射(XRD)、AFM和Hall测量研究1μm厚本征GaN外延薄膜的结晶质量、表面粗糙度、背底载流子浓度和迁移率等性能,发现随着LTGaN缓冲层厚度的增加:XRD的半高宽FWHMs增大,表面粗糙度先减小后又略有增大,背底载流子浓度则随之减少,而迁移率的变化则不明显。通过分析进一步确认LTGaN缓冲层的最优生长时间。The influence of the low-temperature GaN (LT-GaN) buffer layer thickness on the structural and electrical properties of GaN film by metalorganic chemical vapor deposition was investigated. It is found that with increase of the thickness, the porous surface of LT-GaN buffer layer is becoming flatter and denser. The surface average roughness of GaN film is examined by atomic force microscopy (AFM). The results show that with the increase of LT-GaN buffer layer thickness the FWHMs of ω(0002) for GaN films increase, the carrier concentrations decrease, but the surface roughness of GaN films decreases firstly and then increases slightly and mobilities don't change apparently. An appropriate thickness is found and results in the better structure, surface roughness and electrical properties of the GaN film.

关 键 词：缓冲层厚度 GAN 蓝宝石衬底 MOCVD 

分 类 号：O484[理学—固体物理]