Investigation of dislocations in 8° off-axis 4H-SiC epilayer

• Published in: Chinese physics B 2010-07, Vol.19 (7), p.425-429
• Main Author: 苗瑞霞 张玉明 张义门 汤晓燕 盖庆丰
• Format: Article
• Language: English
• Subjects: SiC; TEDS; 刃型位错; 外延层; 扫描电子显微镜; 腐蚀形貌; 逃生装置
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/19/7/076106

This paper reports that the etching morphology of dislocations in 8° off-axis 4H-SiC epilayer is observed by using a scanning electronic microscope. It is found that different types of dislocations correspond with different densities and basal plane dislcation （BPD） array and threading edge dislocation （TED） pileup group lie along some certain crystal directions in the epilayer. It is concluded that the elastic energy of threading screw dislocations （TSDs） is highest and TEDs is lowest among these dislocations, so the density of TSDs is lower than TEDs. The BPDs can convert to TEDs but TSDs can only propagate into the epilyer in spite of the higher elastic energy than TEDs. The reason of the form of BPDs array in epilayer is that the big step along the basal plane caused by face defects blocked the upstream atoms, and TEDs pileup group is that the dislocations slide is blocked by dislocation groups in epilayer.