Influence of donor impurities and crystal faces on doping-dependent fixed charges in SiC/SiO 2 structure

Abstract Unique fixed charges in SiC/SiO 2 structures, whose density depends on the doping concentration and the final annealing temperature, were further investigated by varying impurity species (nitrogen and phosphorus) and crystal faces, such as SiC (0001), (11 2 ¯ 0), and (1 1 ¯ 00) faces. The relationship between the fixed charge density and doping concentration is almost independent of the n-type impurity species. By increasing the doping concentration, the density of negative fixed charges increases regardless of the crystal faces, though the doping dependence was found to be slightly weaker at the (11 2 ¯ 0) and (1 1 ¯ 00) interfaces, compared to the (0001) interface. These findings support the authors’ proposed mechanism of fixed-charge formation; Defect formation related to the Fermi level during the final annealing process.