Direct Observation of the Energy Distribution of Interface States at SiO 2 /4H-SiC Interface: Operando Hard X-ray Photoelectron Spectroscopic Study

The energy distribution of the interface states at the SiO 2 / 4H-SiC(0001) interface was obtained using operando hard x-ray photoelectron spectroscopy. For the energy distribution, two components exsisted. The sharp and high density interface states were observed near the conduction band minimum (CBM) while uniform interface states were present in the entire SiC band-gap. The uniform interface states in the whole gap were assigned to graphitic carbon clusters at the interface while the sharp interface states near CBM could not be clarified in the present study.