Characterization of silicon dioxide films on 4H-SiC (0001) Si, (1-100) M, and (11-20) A faces by cathodoluminescence spectroscopy

Abstract

We prepared SiO2 films with channel mobilities (CMs) of 35, 105, and 112 cm2/Vs on 4H-SiC (0001) Si, (1-100) M, and (11-20) A faces by post-oxidation annealing (POA) in NO ambient and measured the cathodoluminescence (CL) spectra. For an acceleration voltage of 5 kV, the CL peak assigned to oxygen vacancy centers (OVCs) weakens by POA, whereas the CL peak related to Si-N bonding structures intensifies with increasing CM. This suggests that OVCs in the SiO2/SiC interface are terminated by N. We show that NO ambient POA increases the CM more effectively than that by N2O ambient. CL spectroscopy provides us with extensive information on OVCs, non-bridging oxidation hole centers, and dangling bonds in the SiO2/SiC interface on 4H-SiC substrates and on the CM in n-type MOS capacitors.