The effects of incorporating nitrogen into silicon dioxide on gate leakage current in MOSFETs

Based on the first principles calculations, the band structure properties of lightly nitride silicon oxide are studied. Two gate leakage current mechanisms were found: one is direct tunneling, the other is defect assisted tunneling for higher nitrogen atom concentration. The tunneling currents through silicon dioxide/SiO_1.875N_0.083 stacks were calculated. The calculated results show that the gate leakage current can be reduced largely for a small nitrogen atom concentration. In other words, silicon oxynitride dielectric film with a special nitrogen atom concentration can greatly extend the oxide-equivalent thickness