As the general method of defect characterization is destructive, duringthe current research on the effect of defect on device, nondestructive defectcharacterization is important especially. The defects of 4H-SiC homoepitaxiallayer had been observed and studied, based on the principle ofcathodoluminescence(CL). The results show that the intrinsic stacking faults(SFs), threading edge dislocations(TEDs), threading screw dislocations(TSDs) andbasal plane dislocations(BPDs) can be observed by cathodoluminescence. The shapeare rightangle triangle, dot and stick, repectively. So this method is availablefor nondestructive defect characterization. The correlation between 4H-SiCsubstrate defects and epilayer defects will be established if we characterize thedefects of 4H-SiC wafers with and without an epilayer. In addition, if wecharacterize the defects of device before and after operation, the correlationbetween SiC defects of the devices before and after operation will beestablished, too.characterization； Dislocations and stacking faults防基金项目(9140A08050508)资助