摘要
利用高分辨X射线衍射仪(XRD)分析了长时间退火前后的GaN样品.通过对各个样品的(0002)面摇摆曲线进行线形拟合及分析,发现虽然退火后摇摆曲线的半峰宽变大,但面外倾斜角(tilt)的值却变小,从而螺型穿透位错(TD)密度变小,这与化学腐蚀实验的结果一致.我们的结果表明,线形拟合在利用XRD研究GaN薄膜材料结构的过程中是十分必要的,而不能用摇摆曲线的展宽直接表征TD密度.
High-resolution X-ray diffraction is utilized to analyze the micro-structure of annealed and as-grown GaN thin films grown by metalorganic chemical vapor deposition. Profile-fitting analyses indicate that the annealed ones have larger full widths at half maximum of （0002） rocking curve and lower densities of screw-type threading dislocations than the asgrown samples. A chemical etching experiment supports the above results. Our results indicate that profile-fitting is necessary when XRD is used to characterize the structure of GaN thin films.
基金
国家自然科学基金资助项目(批准号:60376005)~~
关键词
高分辨XRD
摇摆曲线
穿透位错
high-resolution X-ray diffraction
rocking curve
threading dislocation
