Raman scattering investigation of defects in thick homoepitaxial 4H-SiC films

Three types of defects, namely comet I, comet II and carrot, in thick 4H-SiC homoepilayer were investigated by the micro-Raman scattering measurements. Comet defects were originated from certain cores which caused by the point defects or the inclusions on the surface of the substrate. 3C-SiC inclusions, which were not contained in carrot, were found in comet defects. The different distribution of 3C-SiC in comet I and comet II was investigated by using micro-Raman scattering measurement. The formation mechanisms of these three defects were discussed.