Electrically detected magnetic resonance study on interface defects at nitrided Si-face, a-face, and m-face 4H-SiC/SiO2 interfaces

Abstract

We investigated interface defects formed on a-face and m-face 4H-SiC/SiO2 interfaces after interface nitridation by nitric oxide (NO) post-oxidation annealing (POA). Using electrically detected magnetic-resonance spectroscopy, we observed interface defects on these faces. The a- and m-face interface defects were found to be similar to a carbon-related interface defect (the PbC center) observed on the standard Si-face, but their amounts were significantly lower than those of the Si-face after the same NO POA. Such a reduction was correlated with a drastic increase in the field-effect mobility (80–90 cm2 V−1 s−1) of the a- and m-face metal-oxide-semiconductor field-effect transistors after NO POA. We also found that over-nitridation caused the formation of two types of nitrogen-related defects on the Si-face. These nitrogen-related defects resemble the K center (Si dangling-bond center) observed in Si3N4.