An attempt was made to reveal the effect of micropipes and planar defects upon the polishing characteristics of SiC wafers. The wafers were lapped and finish-polished using chemical-mechanical polishing. The surface finish examinations were performed by using atomic force microscopy along with a stylus instrument and revealed that for SiC wafers with a low defect density the average surface roughness was less than 5A. It was found that scratches were generated due to chipping of the walls of micropipes and planars. Moreover, depending on the micropipe density, wavy features or so-called orange peel were 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 micropipe density exceeds 100/cm2.

Influence of Structural Defects on the Polishing of Silicon Carbide Single Crystal Wafers. R.T.Bondokov, T.Lashkov, T.S.Sudarshan: Japanese Journal of Applied Physics –1, 2004, 43[1], 43-9