Predictive Modeling of the NBTI Effect for Reliable Design

Abstract

This paper presents a predictive model for the negative bias temperature instability (NBTI) of PMOS under both short term and long term operation. Based on the reaction-diffusion (R-D) mechanism, this model accurately captures the dependence of NBTI on the oxide thickness (tox), the diffusing species (H or H2) and other key transistor and design parameters. In addition, a closed form expression was derived for the threshold voltage change (DeltaVth ) under multiple cycle dynamic operation. Model accuracy and efficiency were verified with 90-nm experimental and simulation data. The impact of NBTI was further investigated on representative digital circuits