斜切蓝宝石衬底MOCVD生长GaN薄膜的透射电镜研究

摘要

Quality properties and internal defects of unintentionally doped GaN films grown on 0.3~ vicinal sapphire (0001) substrates by MOCVD are investigated by TEM. The results show that plenty of dislocations in the GaN films prepared on vicinal sapphire substrates are annihilated in the areas with a distance of 0.8 [xm away from substrates, and that dislocations gather in the GaN films. Based on these phenomena, a mechanism for dislocation annihilation in the GaN film prepared on vicinal substrate is proposed, which is capable of explaining the fact that vicinal substrates are able to improve the qualities of GaN films.%利用MOCVD技术在斜切角度为0．3。的c面蓝宝石衬底上生长了非故意掺杂GaN薄膜，并采用透射电子显微镜对材料的质量和材料内部缺陷进行了分析．研究发现斜切蓝宝石衬底上外延的GaN材料中，位错在距离衬底0．8um附近大量湮灭，同时位错扎堆出现．基于上述现象，提出了斜切衬底上GaN材料中位错的湮灭机制，解释了斜切衬底能够提高GaN晶体质量的原因．