Comprehensive identification of novel origins of single Shockley stacking faults in 4H-SiC using UV irradiation and non-destructive defect characterization

Abstract

We investigated the origins of single Shockley stacking faults (1SSFs) that expanded from basal plane dislocations (BPDs) in a 4H-SiC epitaxial wafer, with the aim of comprehensively identifying all possible origins that cause bipolar degradation in SiC power devices. By analyzing photoluminescence images X-ray topography images before and after ultraviolet-induced 1SSF expansion, we inferred the origin of 1SSFs from the images obtained during expansion. This method enabled large-scale evaluation of 1SSF origins in the wafer. The origins included well-known BPDs in the substrate and propagated BPDs. Additionally, we identified origins related to the surface region and a threading mix dislocation. The results of this study will contribute to developing strategies for reducing BPDs and other defects that cause 1SSFs, thereby improving the long-term reliability of SiC-based power devices.