Effect of oxidation method and post-oxidation annealing on interface properties of metal-oxide-semiconductor structures formed on n-type 4H-SiC C(000(1)over-bar) face

The C(<000(1)over bar>) face of silicon carbide (SiC) has superior properties such as a faster oxidation ratio and a smoother surface compared with the Si(0001) face. We have investigated the oxidation and post-oxidation annealing effects on the capacitance-voltage and the interface state density (D-it) of n-type SiC metal-oxide-semiconductor (MOS) structures formed on the C(<000(1)over bar>) face. It was found that pyrogenic oxidation and hydrogen annealing above 700 degrees C reduced D-it near the conduction-band edge. The value of D-it at E-c-E = 0.2 eV is 1 x 10(12) eV(-1) cm(-2), which is comparable with that of the MOS structure formed on the Si(0001) face. However, the value of D-it around the deep level at E-c-E=0.6 eV is one order of magnitude higher than that of n-type MOS structures formed on the Si(0001) face. It is very important to reduce D-it at the deep level for a high-quality SiO2/SiC interface on the 4H-SiC C(<000(1)over bar>) face. (C) 2000 American Institute of Physics. [S0003-6951(00)01832-5].