[Calculation of dislocation destiny using X-ray diffraction for 4H-SiC homoepitaxial layers].

A theoretical and experimental study on calculating dislocation destiny for 4H-SiC homoepitaxial layers has been carried out. There is some difficulty in measuring dislocation density if it is more than 10(6) * cm(-2). In the paper, a theoretical analysis is made about the effects of dislocation density on the results of X-ray diffraction, and the relationship of dislocation density and FWHM spread is obtained. Then the X-ray diffraction curves of 4H-SiC in omego2theta with two different crystal faces are presented from which the density of dislocation is calculated. According to the result, the cause of dislocation origin is analyzed and the methods of decreasing dislocation density are proposed.

[The study of nondestructive defect characterization of SiC by cathodoluminescence].

As the general method of defect characterization is destructive, during the current research on the effect of defect on device, nondestructive defect characterization is important especially. The defects of 4H-SiC homoepitaxial layer had been observed and studied, based on the principle of cathodoluminescence (CL). The results show that the intrinsic stacking faults (SFs), threading edge dislocations (TEDs), threading screw dislocations (TSDs) and basal plane dislocations (BPDs) can be observed by cathodoluminescence. The shape are rightangle triangle, dot and stick, repectively. So this method is available for nondestructive defect characterization. The correlation between 4H-SiC substrate defects and epilayer defects will be established if we characterize the defects of 4H-SiC wafers with and without an epilayer. In addition, if we characterize the defects of device before and after operation, the correlation between SiC defects of the devices before and after operation will be established, too.