预辅Al及AlN缓冲层厚度对GaN/Si(111)材料特性的影响

Effects of AlN Buffer Layer Thickness and Al Pre-Treatment on Properties of GaN/Si(111) Epilayer

主要研究了采用高温AlN缓冲层外延生长GaN/Si(111)材料的工艺技术。利用高分辨X射线双晶衍射(HRXRD)分析研究了GaN/Si(111)样品外延层的应变状态和晶体质量,通过原子力显微镜(AFM)分析研究了不同厚度的高温AlN缓冲层对GaN外延层的表面形貌的影响。实验结果表明,AlN缓冲层生长前预通三甲基铝(TMAl)的时间、AlN缓冲层的厚度对GaN外延层的应变状态、外延层的晶体质量以及表面形貌都有显著影响。得到最优的预辅Al时间为10s,AlN缓冲层的厚度为40nm。在此条件下外延生长的GaN样品(厚度约为1μm)表面形貌较好,X射线衍射(XRD)双晶摇摆曲线半峰全宽(FWHM)(0002)面和(10-12)面分别为452″和722″。

The technology of epitaxy growth GaN/Si （111） with high temperature AIN buffer is investigated. The state of strain and crystalline quality of GaN epitaxial layer on Si（111） substrate is investigated by high resolution X- ray double crystal diffraction （HRXRD）. The influence of the high temperature AIN buffer thickness on the surface morphologies of GaN films is characterized by the atomic force microscopy （AFM）. The experimental results show that the A1 pre-treatment time and the thickness of A1N buffer have a significant influence on the crystalline quality, state of strain and surface morphology of GaN. The optimal A1 pre-treatment time is 10 s, and the thickness of A1N buffer is 40 nm. The good surface morphology of GaN epitaxial layer is obtained with the full width at half maximum （FWHM） of GaN （0002） of 452＂, and （10-12） of 722＂ by X-ray （XRD） double crystal diffraction.