Silicon carbide CVD homoepitaxy on wafers with reduced micropipe density

CVD growth experiments have been performed on reduced micropipe density (<20 cm−2) 4H and 6H–SiC substrates. Clearly visible prior to CVD growth was a large degree of step-bunching (i.e. macrosteps) and triangular defects resulting from the process used to reduce the micropipe density. After CVD growth; a reduction in the surface roughness was achieved along with a reduction of triangular defect density. The CVD experiments were repeated on reduced micropipe density 6H–SiC substrates with a similar, but not as dramatic, reduction in the surface roughness. KOH etching was performed after CVD growth indicating the micropipe density in CVD layers did not exceed that in SiC substrates after micropipe filling. Therefore a CVD buffer layer, similar to the layers grown during these preliminary experiments, could serve to finish the process of micropipe density reduction from the substrate that was begun with the initial micropipe filling process.