Investigation of Dislocation Behavior during Bulk Crystal Growth of SiC

Abstract

Dislocation behavior during physical vapor transport (PVT) growth of silicon carbide (SiC) single crystals has been investigated by defect selective etching and transmission electron microscopy (TEM). It was found that foreign polytype inclusions introduced a high density of basal plane dislocations at the polytype boundary, while in the polytype-transformed areas of the crystal, the density of medium size hexagonal etch pits due to threading screw dislocations was significantly reduced, indicating that the polytype transformation tended to cease the propagation of threading screw dislocations. Oval-shaped etch pit arrays observed on the etched vicinal (0001)Si surface, indicative of the dislocation multiplication in the basal plane, showed characteristic distribution around micropipes and low angle grain boundaries. Based on the results, we have argued dislocation behavior in PVT grown SiC crystals, suggesting that dislocation interaction and conversion are relevant processes to understanding the behavior.