Photoemission study of the initial oxidation of 6H-SiC(0001¯)-(2×2)C

Initial oxidation of 6H-SiC(0001¯)-(2×2)C surface was studied at different conditions by photoelectron spectroscopy using synchrotron radiation (SRPES). Oxidation process is performed at room temperature and at 800 °C under different oxygen pressures. It was found that oxygen atoms prefer bonding with the bilayer silicon atoms located below the top surface, while the topmost adatoms are hardly oxidized at room temperature even at very high oxygen exposure. However, by elevating the temperatures and oxygen pressures, the SiC surface was oxidized and the thickness of the oxide layer was estimated, taking the refraction effect of low energy photoelectrons into account.