An analysis Of the benefits of NBTI recovery under circuit operating conditions

A simple but powerful and efficient NBTI recovery model is presented. Calibration is performed with a wide set of stress and recovery sequences measured under various voltages. The model provides easy-to-use tools for analytical representation of NBTI behavior as well as compatibility for sophisticated circuit reliability simulations. Regarding circuit operation and transistor characterization, the model implies higher permanent damage and thus, less recoverable NBTI degradation as the V_DD is increased. Furthermore, the activity of the transistors inside a circuit becomes very critical to understand the impact of recovery. The duty cycle and frequency trends are not sufficient to judge for the amount of circuit-level aging. Even the circuit topology contributes to the final degradation, and therefore recovery should be analyzed within the context of the circuit applications.