Physical properties of N2O and NO-nitrided gate oxides grown on 4H SiC

${\mathrm{N}}_{\mathrm{2}}\mathrm{O}$ and NO nitridation by either annealing or direct growth of gate oxides on 4H SiC is analyzed in this letter. The analysis is based on x-ray photoelectron spectroscopy binding energies and secondary ion mass spectroscopy depth profiles of nitrogen at the ${\mathrm{SiO}}_{\mathrm{2}}\mathrm{–SiC}$ interface. A clean ${\mathrm{SiO}}_{\mathrm{2}}\mathrm{–SiC}$ interface is found in both NO and ${\mathrm{N}}_{\mathrm{2}}\mathrm{O}$ annealed/grown samples, as opposed to the interface annealed in Ar which exhibits complex suboxides and oxide–carbon compounds. The results demonstrate that nitridation in the industry-preferred ${\mathrm{N}}_{\mathrm{2}}\mathrm{O}$ ambient could be as effective as nitridation in NO, provided appropriate process optimization is performed.