Statistical NBTI-effect prediction for ULSI circuits

Static statistical variability and time-dependent reliability are traditionally analyzed separately. This paper presents a new methodology which combines both types of variability within a single circuit analysis framework. A comprehensive Negative Bias Temperature Instability (NBTI) model was implemented. Effects of random discrete dopants, line edge roughness and poly-Silicon granularity were considered. Using a 74X-series benchmark circuit (4-bit fast-carry adder) as an example, the concept of integrating both static statistical variability and time-dependent reliability into circuit analysis is demonstrated.