Effects of wet-ROA on shallow interface traps of n-type 4H-SiC MOS capacitors

The effects of wet re-oxidation annealing(wet-ROA) on the shallow interface traps of n-type 4H-SiC metal–oxide–semiconductor(MOS) capacitors were investigated by Gray–Brown method and angle-dependent Xray photoelectron spectroscopy technique. The results present the energy distribution of the density of interface traps(Dit/ from 0 to 0.2 eV below SiC conduction band edge(EC/ of the sample with wet-ROA for the first time,and indicate that wet-ROA could reduce the Dit in this energy range by more than 60%. The reduction in Dit is attributed to the reaction between the introduced oxygen and the SiOxCy species,which results in C release and SiOxCy transformation into higher oxidation states,thus reducing the SiOxCy content and the SiOxCy interface transition region thickness.