Defect formation during the initial stage of physical vapor transport growth of 4H-SiC in the [112¯0] direction

Defect formation during the initial stage of physical vapor transport (PVT) growth of 4H-SiC in the [112¯0] direction has been investigated by x-ray reciprocal space mapping (RSM), defect-selective etching, and low-voltage scanning electron microscopy. RSM studies showed that 4H-SiC crystals grown in the [112¯0] direction showed a significant degradation of crystalline quality during the initial stage of PVT growth, compared with crystals grown in the [0001¯] direction; the growth in the [112¯0] direction resulted in a misoriented domain structure near the grown crystal/seed interface. At the interface, high densities of basal plane dislocations, extending parallel to the interface, and threading edge dislocations along the c-axis were observed. The former caused a tilt domain boundary around an axis parallel to [11¯00]. Based on the results, the paper discusses the defect formation mechanism during the initial stage of PVT growth in the [112¯0] direction and points to the difference in nitrogen concentration between the seed and the grown crystal as a cause of the observed domain and dislocation structure at the grown crystal/seed interface.