Structural properties of subgrain boundaries in bulk SiC crystals

The structural properties of subgrain boundaries (low-angle grain boundarie s) in bulk SiC crystals have been studied using high-resolution X-ray diffr action (HRXRD) and molten KOH defect selective etching. The defect-selectiv e etching revealed that the subgrain boundaries were polygonized into (1 (1 ) over bar 00) directions and most often occurred at the peripheral parts o f crystals. The relative misorientation between adjacent subgrains was exam ined by HRXRD, and it was found that the tilting of the (0 0 0 1) lattice p lane occurred at the subgrain boundaries and had a rotation axis parallel t o both the boundary plane and the (0 0 0 1) basal plane. Based on these res ults, we have discussed the cause and mechanism of the formation of subgrai n boundaries in bulk SiC crystals. (C) 2000 Elsevier Science B.V. All right s reserved.