Mechanism of negative bias temperature instability for PMOSFET's with thin gate oxide

The negative bias temperature instability (NBTI) of deep-submicron PMOSFETs has been investigated. NBTI includes both interface states generation and positive fixed oxide charges formation in the gate oxide, which play major roles for its degradation mechanism. The degradation characteristics of PMOSFETs are investigated thoroughly. A simple degradation model is proposed that fully accounts for this observation.