Surface chemical states on LPCVD-grown 4H-SiC epilayers

A series of 4H-silicon carbide (SiC) epilayers grown on 4H-SiC substrates by low pressure chemical vapor deposition (LPCVD) with different silane (SiH4) to propane (C3H8) gas flow ratios were studied by angle resolved X-ray photoelectron spectroscopy (ARXPS) and atomic force microscopy (AFM). ARXPS revealed that the surfaces of the samples consisted of elemental Si, Si oxides (SiO2 and SiOx where x