CHEMICAL ETCHING OF THERMALLY-GROWN SIO2-FILMS ON SIC STUDIED BY SPECTROSCOPIC ELLIPSOMETRY

Chemical etching characteristics of thermally grown SiO2 filMS on 6H-type SiC in aqueous HF solutions have been studied using spectroscopic ellipsometry. Aqueous HF (1.5%) solution can etch thermally grown SiO2 layers on the (0001)Si and (0001BAR)C faces of SiC at a rate of approximately 90 angstrom/min. A linear regression analysis and an effective medium approximation indicate that the SiO2/(0001)Si interface formed by thermal oxidation, followed by aqueous HF etching, is much rougher than the SiO2/(0001BAR)C interface produced by the same procedure.