The potential of using the optical stress technique to delineate the various defects in SiC wafers was fully demonstrated. The observed defects include micro-pipes, dislocations, stress striations, grain boundary or dislocation walls, and regions of polytype non-uniformity. The revealed dislocation densities ranged from 104 to 105/cm2.

Nondestructive Defect Delineation in SiC Wafers Based on an Optical Stress Technique. X.Ma, M.Parker, T.S.Sudarshan: Applied Physics Letters, 2002, 80[18], 3298-300