Fabrication processes of metal-oxide semiconductor (MOS) capacitors on n-type, Si-face, 6H-SiC were studied. The effects of thermal oxidation conditions at temperatures between 1100 and 1250°C on the electrical properties of MOS capacitors were determined. The wafers were annealed under argon to improve the C-V characteristics. C-V characteristics of AI-SiO2-SiC metal-oxide-semiconductor were measured at high frequency in the dark and under illumination. In the dark inversion does not occur, probably owing to the absence of minority carriers due to the large band gap of 6H-SiC. The accumulation, depletion, and inversion regions were clearly observed when the C-V measurements were made under illumination for both wet and dry thermally grown oxides. The interface trap densities and emission time constants of fast states were determined by ac conductance measurements. From the analysis of data we obtained a total of Fixed charges and the slow interface traps, Nf + NssSlow of 1.5 to 3.3 × 1012 cm-2, fast interface trap densities, NssFast of 0.5 to 1.7 × 1011 cm-2 eV-1 and emission times constant of 0.3 to 1.4 μsec for wet oxidation. For dry oxidation, Nf + N, ssSlow of 3.5 to 11.2 × 10cm-2, NssFast of 0.7 to 1.25 × 1010 cm-2 eV-1 and emission time constants of 0.6 to 2 μsec were obtained.