Interface properties of metal-oxide-semiconductor structures on n-type 6H and 4H-SiC

Abstract

This work reports on the interface properties of metal‐oxide‐semiconductor (MOS) structures formed by thermal oxidation of n‐type silicon carbide (SiC). The SiC layers, grown homoepitaxially on the silicon‐face of 6H‐SiC and 4H‐SiC substrates, were oxidized at 1100 °C in dry or wet atmosphere. The interface properties of the MOS structures were investigated using both, the Terman and the high‐low frequency method. The validity of these methods for wide band‐gap semiconductors is clarified in a short theoretical analysis. The experimental results reveal moderate densities of interface states for MOS devices on 6H‐SiC as well as on 4H‐SiC. Only minor differences were observed between both polytypes. Current‐voltage measurements prove earlier results and show good quality independent of the polytype used as substrate material.