Leak current mechanisms in NO-nitrided SiC(100) MOS devices

Suzuki, Asato*; Nakanuma, Takato*; Kobayashi, Takuma*; Sometani, Mitsuru*; Okamoto, Mitsuo*; Yoshigoe, Akitaka ; Shimura, Takayoshi*; Watanabe, Heiji*

Gate leakage mechanism in NO-nitrided SiC(100) MOS devices was investigated. Experimental current density-oxide field characteristics at 25-200C were reproduced assuming Fowler-Nordheim (FN) and Poole-Frenkel (PF) mechanisms. Although NO nitridation is effective in improving the channel mobility of SiC MOSFETs, the nitridation reduces the conduction band offset at the SiO/SiC interface and increases the FN current. Furthermore, it was found that the nitridation cannot remove the defects that cause the PF current.