A study on N2O direct oxidation process with re-oxidation annealing for the improvement of interface properties in 4H-SiC MOS capacitor

The effect of N2O direct oxidation processes with re-oxidation on SiC/SiO2 interface characteristics has been investigated. With different oxidation and post oxidation annealing (POA) processes, the flat-band voltage, effective dielectric charge density, and interface trap density are obtained from the capacitance-voltage curves. For the proposed N2O direct oxidation processes with re-oxidation, oxides were grown in N2O ambient, diluted in high-purity N2 to 10% concentration, for 5 h at 1230 °C. After the growth, some samples were annealed additionally at 1200 °C in O2 or H2O for 20 min. N2O direct oxidation with re-oxidation processes was confirmed that SiC/SiO2 interface properties and dielectric stability have better performance than with other conventional oxidation processes. This oxidation technique is expected to improve gate dielectric stability for application to SiC MOS devices; in particular, it can be used to obtain high-quality SiC/SiO2 interface properties.