R&D of 1200V SiC MOSFETs with Nitrided Gate Oxide and Self-aligned Channel Technology

The fabrication of 1200V SiC MOSFET with developed nitrided gate oxide and self-aligned channel technology are reported. Post-oxidation annealing in nitrogen-contained ambient can effectively passivate defects at the SiC/SiO2 interface which is beneficial for the mobility improvement in SiC MOSFETs. The process of nitridation begins from the conduction band and extends to the mid-band-gap gradually. Our newly developed self-aligned channel technology, where side wall and poly-silicon are used as mask instead of traditional metal mask, is efficient in shortening the MOSFET channel to half micro, which helps reduce the channel length of the device. With these two technologies mentioned above, 1200V SiC MOSFET is fabricated based on our own process line. And the current capability increases markedly after gate oxide nitridation and self-aligned channel treatment.