Defect-based compact model for circuit reliability simulation in advanced CMOS technologies

Abstract

A defect-based compact modeling approach for circuit reliability simulation based on surface potential calculations is presented. The modeling approach captures the bias-dependence of stress-induced defects such as (bulk) oxide-trapped charge and interface traps that cannot be described by typical fixed voltage shift models (i.e., threshold voltage, Vth-based models). The defect dynamic charge contribution is modeled under non-equilibrium conditions and for all regions of operation (i.e. from weak to strong inversion) and not just at the threshold (as in Vth-based models). The modeled is verified with 2-D TCAD simulations that incorporate oxide trapped charge and interface trap densities. Spice-level simulations of ring oscillators and SRAM cells reveal inaccuracies in describing aging effects when utilizing typical fixed voltage shift models as compared to the presented defect-based compact modeling approach.