Optical microscopy, synchrotron white beam X-ray topography, and high resolution X-ray diffraction were used to study the distribution of basal plane dislocations in bulk 4H SiC crystals grown by the physical vapor transport method. An etch pit array was observed on the Si face of KOH-etched off-cut wafers. The arrays were aligned parallel to each other and perpendicular to the off-cut direction. The etch pits were oval-shaped, which was characteristic of basal plane dislocations. Corresponding array images were observed by synchrotron white beam X-ray topography. Based on the characteristic distribution, the etch pit arrays were interpreted as the slip traces of high temperature deformation during the growth process. Thermoelastic stress was proposed as the plausible cause of the deformation. In addition, basal plane dislocation pileups were found in the proximity of polygonized threading edge dislocation arrays. Synchrotron white beam X-ray topography and high-resolution X-ray diffraction were used to study the misorientation related to such dislocation structure. The pile-ups were interpreted as the origin of the basal-plane-tilt domains in SiC crystals.

Basal Plane Slip and Formation of Mixed-Tilt Boundaries in Sublimation-Grown Hexagonal Polytype Silicon Carbide Single Crystals. S.Ha, M.Skowronski, W.M.Vetter, M.Dudley: Journal of Applied Physics, 2002, 92[2], 778-85