Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence x-ray diffraction  

作　　者：郭希 王玉田 赵德刚 江德生 朱建军 刘宗顺 王辉 张书明 邱永鑫 徐科 杨辉 

机构地区：[1]State Key Laboratory on Integrated Optoelectronics,Institute of Semiconductors,Chinese Academy of Sciences [2]Suzhou Institute of Nano-tech and Nano-bionics,Chinese Academy of Sciences

出　　处：《Chinese Physics B》2010年第7期471-478,共8页中国物理B（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 60506001,60776047,60976045 and 60836003);the National Basic Research Programme of China (Grant No. 2007CB936700);the National Science Foundation for Distinguished Young Scholars,China (Grant No. 60925017)

摘　　要：This paper investigates the major structural parameters, such as crystal quality and strain state of （001）-oriented GaN thin films grown on sapphire substrates by metalorganic chemical vapour deposition, using an in-plane grazing incidence x-ray diffraction technique. The results are analysed and compared with a complementary out-of-plane x- ray diffraction technique. The twist of the GaN mosaic structure is determined through the direct grazing incidence t of （100） reflection which agrees well with the result obtained by extrapolation method. The method for directly determining the in-plane lattice parameters of the GaN layers is also presented. Combined with the biaxial strain model, it derives the lattice parameters corresponding to fully relaxed GaN films. The GaN epilayers show an increasing residual compressive stress with increasing layer thickness when the two dimensional growth stage is established, reaching to a maximum level of-0.89 GPa.This paper investigates the major structural parameters, such as crystal quality and strain state of （001）-oriented GaN thin films grown on sapphire substrates by metalorganic chemical vapour deposition, using an in-plane grazing incidence x-ray diffraction technique. The results are analysed and compared with a complementary out-of-plane x- ray diffraction technique. The twist of the GaN mosaic structure is determined through the direct grazing incidence t of （100） reflection which agrees well with the result obtained by extrapolation method. The method for directly determining the in-plane lattice parameters of the GaN layers is also presented. Combined with the biaxial strain model, it derives the lattice parameters corresponding to fully relaxed GaN films. The GaN epilayers show an increasing residual compressive stress with increasing layer thickness when the two dimensional growth stage is established, reaching to a maximum level of-0.89 GPa.

关 键 词：in-plane grazing incidence x-ray diffraction gallium nitride mosaic structure biaxialstrain 

分 类 号：O484.5[理学—固体物理]