Thickness and etch rate of SiO2 films thermally grown on hexagonal SiC substrates were compared to results obtained from SiO2/Si samples. The data confirm that profilometry and ellipsometry yield the same thickness values for oxides grown on Si and SiC. Within the accuracy of our measurements, oxides grown on different polytypes and faces of SiC etch at the same rate in a HF acid solution. The etch rate using a 50:1 H2O:HF(50%) solution at room temperature is 0.1 nm/s and is uniform throughout the thickness of the SiO2 films. The rate is the same as that obtained for SiO2 grown on Si.