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 crystals grown by using 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 were perpendicular to the off-cut direction. The etch pits were oval, and therefore characteristic of basal-plane dislocations. Corresponding array images were observed by synchrotron white-beam X-ray topography. Based upon the characteristic distribution, etch-pit arrays were interpreted as being the slip traces of high-temperature deformation during growth. Thermoelastic stress was proposed to be a plausible cause of the deformation. In addition, basal-plane dislocation pile-ups 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 misorientations related to such dislocation structures. The pile-ups were interpreted as being the origin of 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