A modified Deal Grove model for the oxidation of 4H-SiC is presented, which includes the removal of the carbon species. The model is applied to data on the oxidation rates for the (0001) Si, (0001̄) C, and (112̄0) a faces, which are performed in 1 atm dry oxygen and in the temperature range 950–1150 °C. Analysis within the model provides a physical explanation for the large crystal-face dependent oxidation rates observed.

Nitric oxide postoxidation anneal results in a significant decrease of defect state density (Dit) near the conduction bandedge of n-4H–SiC at the oxide/(112̄0) 4H–SiC interface. Comparison with measurements on the conventional (0001) Si-terminated face shows a similar interface state density following passivation. Medium energy ion scattering provides a quantitative measure of nitrogen incorporation at the SiO2/SiC interface.

We report on experimental studies of the interactions of oxygen with the 4H– and 6H–SiC surfaces at high temperatures. It is observed that these interactions lead to the growth of passivating SiO2 layers at high O2 pressures, etching of the surfaces at lower pressures, and enhancements of the surface segregation of carbon at still lower pressures. A pressure–temperature phase diagram for the oxidation of SiC containing these three experimentally observed regions is presented.

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Graphitic features are detected on 4H-SiC surface following oxidation and etching using surface enhanced Raman spectroscopy (SERS). The electronic state of the carbon is sp2 on both the Si- and C-faces of 4H-SiC. The structures of the “carbon clusters” consist of two-dimensional graphitic flakes less than 2 nm and one-dimensional polyenes. The degree of graphitization on the C-face SiC is higher than those on the Si-face SiC. This study provides experimental evidence for “carbon clusters” existing on SiC surfaces following oxidation at atmospheric pressure and demonstrates that SERS is an effective technique to probe low concentration species on the SiC surface.