Influence of Structural Defects on the Polishing of Silicon Carbide Single Crystal Wafers

This study attempts to reveal the influence of major defects such as micropipes and planars on the polishing characteristics of SiC wafers. SiC wafers were lapped and finish-polished using chemical-mechanical polishing. The surface finish examinations were performed using AFM along with a stylus instrument and revealed that for SiC wafers with a low defect density the average surface roughness is less than 5 A. Scratches are generated due to chipping of the walls of micropipes and planars. Moreover, depending on the micropipe density (MPD), wavy features or so-called orange peels are created. The quantitative dependence of roughness parameters and the uniformity of surface finish on the micropipe density were evaluated and the occurrence of orange peel was found to increase when the MPD exceeds 100 cm-2. 32 refs.