Low-Temperature Annealing in O2 to Annihilate the Fixed Charges in 4H-SiC/SiO2 Interface Induced by High-N-Density Nitridation Process

A low-temperature annealing process for 4H-SiC/SiO2 stack in O2 ambient was found to annihilate the positive fixed charges induced by the interface nitridation process effectively, while preserving the interface N density. The key to design the post-nitridation annealing process in O2 ambient was proposed as the selection of a relatively low temperature and a sufficiently long duration, which is to selectively trigger the annihilation of fixed charges while suppressing the N-removal from the interface.