Effects of nitridation in gate oxides grown on 4H-SiC

Experiments have demonstrated that nitridation provides critically important improvements in the quality of $SiO2–SiC$ interface. This article provides results and analysis aimed at developing the much needed understanding of the mechanisms and effects associated with both annealing of pregrown oxides and direct growth in NO and $N2O$ environments. According to the model proposed in the article, nitridation plays a double role: (1) creation of strong Si≡N bonds that passivate interface traps due to dangling and strained bonds, and (2) removal of carbon and associated complex silicon–oxycarbon bonds from the interface. This understanding of the effects of nitridation is experimentally verified and used to design a superior process for gate oxide growth in the industry-preferred $N2O$ environment.