Factors affecting the formation of misoriented domains in 6H-SiC single crystals grown by PVT method

Misoriented domains (MDs) are common defects in 6H-SiC single crystals. We performed an experimental study on the formation of MDs in 2-inch 6H-SiC single crystals, Micro-Raman spectroscopy revealed that the polytype of MDs was mainly 4H-SiC. By changing growth conditions, it was found that the MDs' formation was closely related to growth rate and the position of highest temperature relative to growth interface. When the growth rate of ingots was relatively high the MDs were more likely to form. Furthermore, the nearer growth interface the position of highest temperature was, the: larger the size of the MDs. Based on our experimental findings we suggested that the MDs' formation and the polytype switching from 6H- to 4H-SiC were due to too large axial and/or radial temperature gradients. The results would be helpful to improve the quality of SiC single crystals grown by PVT technique. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim