Effect of the Growth Interface Shape on the Thermoelastic Stresses in SiC Crystal Prepared by PVT Technique

The main reason for the formation of dislocations in SiC is owing to the thermoelastic stresses,which are induced by the nonhomogeneous temperature distribution during the crystal growth process in PVT technique.However,the profile of growth interface is believed to influence the generation of thermoelastic stresses,and hence to cause structural defects.Therefore,the effect of the growth interface shape on the thermoelastic stresses was investigated.Here,the temperature and stress fields in the crystal were mainly simulated using different growth interfaces.The results show that the axial temperature gradient of a little concave growth interface is lower than that of the convex and planar interfaces.As for the concave interface,the value of the corresponding shear stress(τrz) and normal stress(σrr),which induces the structural defects and crack in the crystal respectively,is the minimum.