Thermal Oxidation of SiC and Electrical Properties of Al–SiO2–SiC MOS Structure

Abstract

Silicon dioxide layers have been thermally grown on the (0001̄)C face of 6H–SiC at 850–1100°C in wet O₂ and studied by Auger analysis and ellipsometry. These oxide layers are quite homogeneous with a narrow interface width of \lesssim80 Å. The oxide thickness vs, the oxidation time follows the general relationship used for the thermal oxidation of Si. Temperature dependencies of the oxidation rate constants were obtained. C-V characteristics of Al–SiO₂–SiC MOS structures were measured at 10 Hz–1 MHz. The accumulation, depletion and inversion regions are clearly observed under illumination. In the dark, the inversion does not occur, probably owing to the absence of minority carriers because of the large band gap. Frequency dispersion is not observed. The minimum surface-state density is ∼2×10¹²cm^-2eV^-1. The oxide resistivity and the breakdown strength are 2×10¹² Ωcm and 2×10⁶V/cm, respectively.