Vacancy in 6H-Silicon Carbide Studied by Slow Positron Beam

• 来源期刊: 中国物理快报（英文版）
• 年，卷（期）: 2003,（7）
• 页码范围: 1105-1108
• 页数: 4页
• 语种: 英文

摘要

The defect changes in 6H-SiC after annealing and 10 MeV electron irradiation have been studied by using a variable-energy positron beam. It was found that after annealing, the defect concentration in n-type 6H-SiC decreased due to recombination with interstitials. When the sample was annealed at 1400℃ for 30min in vacuum, a 20-nm thickness Si layer was found on the top of the SiC substrate, this is a direct proof of the Si atoms diffusing to surface when annealed at high temperature stages. After 10 MeV electron irradiation, for n-type 6H-SiC, the S parameter increased from 0.4739 to 0.4822, and the relative positron-trapping rate was about 27.878 times of the origin sample, this shows that there are some defects created in n-type 6H-SiC. For p-type 6H-SiC, it is very unclear, this may be because of the opposite charge of vacancy defects.