SiO 2 / 6H-SiC (0001)3×3 initial interface formation by Si overlayer oxidation

We investigate the initial oxidation and SiO2/6H-SiC interface formation by core level photoemission spectroscopy using synchrotron radiation. The results indicate that the direct oxidation of the 6H–SiC(0001)3×3 surface leads to SiO2 formation at low temperatures (500 °C) with a nonabrupt interface having significant amounts of mixed (Si–O–C) and intermediate (Si3+,Si2+,Si+) oxidation products. In contrast, C-free and a much more abrupt SiO2/6H-SiC(0001) interface formation is achieved when predeposited Si overlayer is thermally oxidized at low oxygen exposures and low temperatures (500 °C).