6H-SiC single crystal was grown by the physical vapor transport method. The crystal was cut into several (00•1) wafers and two of the wafers were selected for analysis: the wafer close to the surface of the boule (wafer A), and the wafer close to the substrate (wafer B). The wafers were characterized by a double crystal X-ray diffraction rocking curve. The

rocking curve of wafer A showed a single symmetrical peak with a full-width at half-maximum of 40 arcsec, while that of wafer B showed split peaks, which indicate the existence of sub-grains. Defects, such as dislocations, micro-pipes, sub-grains etc., in the two wafers were studied by KOH etching combined with optical micrography and X-ray topography. Possible relationships between the observed defects and their formation mechanisms in the growth process were considered.

Defect Analysis in Single Crystalline 6H-SiC at Different PVT Growth Stages. S.Wang, J.He: Materials Science and Engineering B, 2001, 83[1-3], 8-12