Gate Leakage Current Conduction Mechanisms in NO Annealing and Dry Gate Oxides Grown on 4H-SiC

Current conduction mechanisms of SiC MOS capacitors on n-type 4H-SiC with or without NO annealing were investigated in this work. Results show that FN tunneling is the dominate current conduction mechanism in the high electrical field, and the barrier height is 2.67 eV and 2.54 eV respectively for experiencing NO annealing and without NO annealing. A higher barrier height for NO annealing sample indicate the effect of N element on the SiC/SiO₂ interface quality. In intermediate oxide electrical field, instead of Trap-assisted tunneling PF emission dominate the current conduction in this region. And the C-V characteristics also show the advantages of NO annealing on the SiC/SiO₂ characteristics. This work will provide significant foundation for the key processing technology of SiC MOS device.