表面处理对蓝宝石衬底的影响

Effect of Surface Treatment on Sapphire Substrate

采用熔融的KOH溶液腐蚀蓝宝石衬底,获得具有三角形图案的腐蚀坑形貌,并对腐蚀坑的三角形形状给出了理论解释。在不同温度和不同的腐蚀时间进行对比结果分析,发现在280℃下腐蚀60 min左右,显示的位错清晰、准确,且最适合随后的横向外延生长。采用高分辨率双晶X线衍射(DCXRD)测试分析,结果表明,预处理对蓝宝石衬底的晶体质量和折射率色散关系几乎没影响,所以,预处理获得一定图案的蓝宝石可作为GaN横向外延的衬底,为降低GaN薄膜的位错密度,获得高质量的GaN薄膜提供有利的保障。

The triangle patterned etched pits have been obtained by etching the sapphire substrate using the melted KOH solution and the interpretation on the triangle shape has been given theoretically.In additional,the results which were obtained under varied etched temperature and time have been compared.The results showed that the dislocation displayed was very clear and accurate,and very suitable for the followed lateral epitaxial growth when the sapphire substrate was etched at 280 ℃ for about 60 min.The crystal quality was analyzed by the high-resolution double crystal X-ray diffraction（DCXRD）.The result indicated that the pretreatment of the sapphire substrate had little effect on the crystal quality and the dispersion of the refractive index.Thus the patterned sapphire can serve as the lateral epitaxial substrate to decrease the dislocation density of GaN films and obtain high quality GaN films.