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.

Keywords: 4H-SiC, N2O direct oxidation, Re-oxidation, POA, Interface trap density, MOS capacitor, XPS