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 [ 11 2 ¯ 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 [ 11 2 ¯ 0 ] direction showed a significant degradation of crystalline quality during the initial stage of PVT growth, compared with crystals grown in the [ 000 1 ¯ ] direction; the growth in the [ 11 2 ¯ 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 [ 1 1 ¯ 00 ] . Based on the results, the paper discusses the defect formation mechanism during the initial stage of PVT growth in the [ 11 2 ¯ 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.