Surface morphology improvement of SiC epitaxy by sacrificial oxidation

Study of the epilayer surface of as received silicon carbide wafers (4H, 6H polytypes) by AFM revealed a class of defect described here as 'nanoislands'. These islands were 3-15nm in height anti occurred at a surface density of approximately 10-30 per mu m(2) and do not appear to have been previously reported. The nanoislands were shown not to be removed by standard procedures such as the RCA clean and UV ozone exposure, Instead we found that sacrificial oxidation followed by dissolution in hydrofluoric acid was effective in removing them, resulting in a much improved surface morphology as compared to the as received epitaxial wafer surfaces.