ON THE PRESENCE OF ALUMINUM IN THERMALLY GROWN OXIDES ON 6H-SILICON CARBIDE

N-type and P-type 6H-Silicon carbide wafers, along with P-type silicon control wafers were oxidized in dry oxygen at 1275 degrees C for 45 m in, Capacitance-voltage measurements on the SiO2 films formed on the N -type 6H-SiC and the silicon control wafers yielded near ideal charact eristics while the SiO2 films on P-type 6H-SiC revealed high effective charge and interface state densities, Secondary Ion Mass Spectroscopy performed on the oxides showed significant levels of aluminum and sod ium in SiO2 on both N-type and P-type 6H-SiC but not on the silicon co ntrol wafers indicating that neither element was introduced during pro cessing. The presence of aluminum in oxides on both types suggests tha t it is not solely responsible for the increased effective oxide charg e and interface state densities commonly observed in oxides formed on P-type 6H-SiC.