Investigation of nitridation and oxidation reactions at SiC/SiO 2 interfaces in NO annealing and modeling of their quantitative impacts on mobility of SiC MOSFETs

Nitridation and oxidation reactions at SiC/SiO 2 interfaces during NO annealing were investigated and their quantitative impacts on the channel mobility were modeled. We evaluated the NO annealing condition dependence of nitrogen atom concentration at the SiC/SiO 2 interfaces ([ N ]) and increased oxide thickness (Δ T OX ), as indices of the nitridation and oxidation reactions, respectively. By using the obtained [ N ] and Δ T OX , the experimental mobility was well reproduced in an empirical formula. This empirical formula enables evaluation of the quantitative impact of the nitridation and oxidation reactions on the mobility. From the empirical formula, it was expected that the mobility would be further increased by lowering the annealing temperature from the investigated temperature range. However, an exponential increase in both NO gas consumption and processing time is also predicted, which leads to the conclusion that the further decrease in annealing temperature would be impracticable.