Chemical characterization of SiO2/SiC interface after nitridation treatment

The nitridation of SiO2/SiC interfaces has shown great promise as a means of achieving high quality gate oxides for SiC MOSFET structures. It is of critical importance to characterize the interfacial nitrogen and understand the beneficial effects of nitridation treatment. In this work, the SiO2/SiC structure was prepared by direct oxidation in nitrous oxide (N2O), followed by a nitric oxide (NO) post-annealing. X-ray absorption spectroscopy (XAS) of Si L- and K-edges, recorded simultaneously in the surface sensitive total electron yield and the interface/bulk sensitive fluorescence yield, have been used to investigate the SiO2/SiC interface of a series of samples after the nitridation treatment. The results show that nitridation introduces nitrogen into the SiO2/SiC interface to form silicon nitride (SiN bonds). Oxygen has also possibly been incorporated into SiO2/SiC interface in the oxynitride form. Great sensitivity of XAS in probing Si, SiC, SiO2 and SiNx at different depths is also demonstrated.