Evolution and stability of basal plane dislocations during bulk growth of highly n-type doped versus highly p-type doped 6H-SiC

摘要

The movement of basal plane dislocations (BPDs) in SiC enhances the formation of stacking faults (SFs), which are believed to be a major hindrance in realizing SiC based bipolar devices of high performance and reliability for high power device applications. In this work, we report for the first time on the evolution and stability of BPDs in highly p-type doped SiC compared with conventional highly n-type doped SiC for improved bipolar devices. Using sequentially doped p-type / n-type / p-type SiC single crystals (sequential doping was done in single growth runs) we investigated the occurrence of BPDs in n-type doped SiC versus p-type doped SiC to address their evolution and stability depending on doping type. We have found, that BPDs are absent or appear significantly less pronounced in p-type doped SiC as compared to n-type doped SiC, a phenomenon which is of great importance to the stacking fault problem in SiC and hence to the performance and reliability of SiC based bipolar devices.