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 wa s 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 redu ction of triangular defect density. The CVD experiments were repeated on re duced micropipe density 6H-SiC substrates with a similar, but not as dramat ic, 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, si milar to the layers grown during these preliminary experiments, could serve to finish the process of micropipe density reduction from the substrate th at was begun with the initial micropipe filling process. (C) 1999 Elsevier Science S.A. All rights reserved.