A study of negative bias temperature instability (NBTI) in pFETs

Abstract

A model for the negative bias temperature instability (NBTI) is proposed. This model is derived from physics principles. The model attributes NBTI to de-passivation of SiO2/Si interface and its two distinguishing features are: application of statistical mechanics to calculate de-passivated site density increase as a function of stressing conditions and the assumption that the hydrogen diffusion in oxide is dispersive. The model is verified using NBTI data for pFETs with poly silicon and metal gate and oxides of varying thickness.