Influence of direct-tunneling gate current on negative bias temperature instability in ultra-thin gate oxides

In this work, the influence of direct-tunneling gate current on negative bias temperature instability (NBTI) was investigated using p⁺-gate and n⁺-gate/pMOSFETs having ultra-thin SiON films as gate dielectrics. As a result, it was found that an electron energy injected from the gate electrode does not affect on a threshold voltage shift (ΔV_TH) and an interface-state generation (ΔI_CP). However, the correlation between NBT degradation and the gate leakage current was observed, irrespective of the gate electrode type. This result suggests that the fluence of injected carriers has an effect on NBT degradation in the case of ultra-thin gate dielectrics.