Thermal stress according to growth temperature and surface region of single crystal SIC was analyzed using ABAQUS simulation. Three 6H SiC single crystal wafers grown with the PVT method under the same growth conditions by different companies were used to analyze the changes in properties caused by thermal stress. All three wafers differed in diffraction distance. The wafer with the higher tensile stress from thermal stress showed a larger diffraction distance. Also the impact of thermal stress on crystallinity and defect density was analyzed. Our results showed that the wafer with the higher thermal stress had lower crystallinity and more defects, and we also confirmed that the wafer had a lower thermal conductivity and bandgap. (C) 2012 Elsevier B.V. All rights reserved.