Improvement of SiO2/4H-SiC Interface Quality by Post-Oxidation Annealing in N2 at High-Temperatures

The efficient and practical method for SiO2/4H-SiC interface improvement using post-oxidation annealing (POA) in pure N2 ambient was studied by means of x-ray photoelectron spectroscopy (XPS) analysis and electrical characterization. SiC-MOS capacitors with slope-shaped thermal oxides were used to investigate optimal conditions for interface nitridation. It was found that the amount of nitrogen atoms incorporated into the interfaces increased when raised the annealing temperature up to 1400°C, and thin oxide (< 30 nm) was used. Furthermore, N2-POA at 1400°C was proven to be very promising as equivalent to NO-POA in terms of reduced interface state density of SiC-MOS devices.