Correlation between surface morphology and breakdown characteristics of thermally grown SiO2 dielectrics in 4H-SiC MOS devices

摘要

We have investigated the surface and interface morphology of a thermally grown SiO2/4H-SiC(0001) structure by atomic force microscopy and transmission electron microscopy. It was found that the surface roughness results in thickness fluctuation of thermal SiO2 due to the pronounced oxidation near the steps. Thus, the localized high elevated electric field near the steps accelerates dielectric degradation and hence results in poor gate oxide reliability.