Characterization of SiC thermal oxidation

Initial stages of in situ oxidation of a n-type 6H-SiC(0 0 0 1) sample were investigated using low energy ion scattering (LEIS) and angle resolved X-ray photoelectron spectroscopy. The very first oxidation products are shown to be silicon oxycarbides (SiCxOy), while for longer oxidation times a mixture of SiCxOy and SiO2 is formed in the near-surface region of the growing film. The composition profile of a much thicker oxide thermally grown on Ar+ irradiated SiC was also investigated. The environment of Si atoms was probed as a function of depth by sequential LEIS and X-ray photoelectron spectroscopy measurements followed by HF etching. The results indicate the existence of a transition region, containing SiCxOy, between a pure stoichiometric layer of SiO2 and the substrate. The analyses also indicate that the SiO2/SiC interface is rough. (C) 2002 Elsevier Science B.V. All rights reserved.