Electric-field dependence of negative-bias temperature instability

To investigate the origin of the electric-field dependence of negative-bias temperature instability (NBTI), we calculated the change in the activation energies of the dissociation reaction of a Si–H bond caused by an electric field. The calculated activation energies show that the change is too small to explain previously reported experimental electric-field dependence. On the other hand, a hole generated by the electric field in the silicon/gate-dielectric interface reduces the activation energy much more. We propose a NBTI mechanism based on the calculated activation energies. This mechanism can be applied to estimate NBTI lifetime over a wide range of electric fields.