Deep-ultraviolet (DUV) micro-Raman spectroscopy was applied to study the micro structures of surface defects in a 4H-SiC homoepitaxially grown film. From DUV Raman spectrum, inclusions of 3C-SiC was found in comet defects. The shape of 3C-structure in comets was investigated and it was found that 3C inclusions in comets can be classified into two types. In addition, spectrum broadening due to the coupling of nonfolded longitudinal optical phonon mode and the photo-excited carriers was also found. The formation mechanisms of 3C inclusion in comets were discussed.