基于图形衬底生长的GaN位错机制分析

Dislocation generation mechanism analysis of GaN grown on patterned sapphire substrate

采用缺陷选择性腐蚀法结合光学显微镜及原子力显微镜(AFM)对金属有机化合物气相外延(MOVPE)在蓝宝石图形衬底(PSS)上生长的非掺杂GaN体材料的位错产生机制进行了研究,分析结果表明,位错来源于三个方面:一是"二步法"生长机制引入的位错;二是是由于图形衬底上不同区域GaN晶体相互连接时由于晶面不连续所造成的位错群;三是由于图形衬底制作工艺过程中引入的表面污染与损伤。

The growth proccess of undoped GaN on patterned sapphire substrate （PSS） was achieved by metal organic vapor phase deposition （MOVPE）. And the defect-selective etching method combined with optical microscope and atomic force microscope （AFM） was carried out to study the mechanism of dislocation generation of GaN on PSS. The results indicate that the dislocation is probably generated from three aspects：＂two-step＂ growth process, the coalsence of GaN crystal from separate areas of PSS,and the substrate surface dmage and contamination during PSS facturing.