SiC籽晶表面状态对晶体质量的影响

为了研究表面状态对晶体质量的影响,本文分别采用腐蚀后抛光与未抛光的晶片作为籽晶,利用金相显微镜对所得晶体进行了显微观察,结果表明:经过腐蚀后抛光的籽晶生长出的晶体质量高于未抛光籽晶所得晶体；生长前端的位错尺寸以及数量小于未抛光籽晶,说明抛光去除了部分表面浅的缺陷腐蚀坑,同时减小深腐蚀坑的尺寸,使得籽晶生长表面的缺陷密度和尺寸大大降低,有助于减少后期生长的晶体中的缺陷密度,提高结晶质量.

Effect of the Surface State of SiC Seed on the Crystal Quality

In order to investigate the effect of the surface state of SiC seed on the crystal quality,the etched wafers with polished surface and unpolished surface were used as the seed crystals.The obtained SiC crystals was observed by optical microscope.The results revealed that the defect density and size in the crystal which used the etched and polished wafer as the seed crystal were smaller than that of crystal which used the unpolished wafer.Because the polishing processing would get rid of some shallow etching pits and reduce the size of deep etching pits,this processing could enhance to shrink defect density and size of seed.It means that etching and polishing processing will reduce the defect density of crystal at the lateral growth stage,and hence to improve crystal quality.