Dislocation Formation During Physical Vapor Transport Growth of 4 H‐SiC Crystals

Several important aspects of defect formation during physical vapor transport (PVT) growth of 4H-SiC bulk crystals are described. The cause and location of formation of basal plane dislocations (BPDs) in PVT-grown 4H-SiC crystals were elucidated through detailed investigations of the BPD distribution in grown crystals. BPDs were revealed to exhibit a characteristic distribution in the crystals, indicating that they were preferentially nucleated at the shoulder region of a growing crystal during PVT growth due to a large thermoelastic stress imposed on the region. The defect formation at the grown crystal/seed interface of PVT-grown 4H-SiC crystals was also investigated using 4H-SiC wafers with a beveled interface between the grown crystal and seed crystal. It was revealed that extended BPD networks were formed at the interface. They migrated deep into the seed crystal during PVT growth through the climb motion of dislocations, which suggests that a large number of vacancies were injected during the initial stage of PVT growth and significantly affected the defect structure at the grown crystal/seed interface.