Characterizations and formation mechanism of a new type of defect related to nitrogen doping in SiC crystals

Abstract

Here, we report a commonly occurring defect related to nitrogen doping in silicon carbide crystals grown by physical vapor transport method while its formation mechanism has remained unclear. It is often mislabeled as planar hexagonal void defect (PHVD) owing to their similar in shape and size on wafer surface. Our results indicate that this is a new type of defect and differs from PHVD with respect to their nitrogen concentrations, void shapes and the connections to micropipe. We found that the carbon-rich vapor during the crystal growth is responsible for the formation of this type of defect. A possible three-stage defect developing mechanism and measures to avoid the defects are proposed.