Interface states and fixed charges in nanometer-range thin nitrided oxides prepared by rapid thermal annealing

Ultra-thin oxides (5-12 nm) were nitrided by lamp-heated rapid thermal annealing in an ammonia ambient at 900-1150°C for 5-300 s. Interface states and fixed charges in the nitrided oxides have been studied, and, for a given temperature, both are found to vary in a similar manner as nitridation time increases: at first both increase, reach respective maxima at a certain nitridation time, and then decrease gradually showing turnarounds. Interface state densities and fixed charge densities at the initial and the final nitridation stages are in the low 10¹⁰- cm^-2/eV range and the low 10¹¹-cm^-2range, respectively, and are comparable with those of thermally grown oxides.