Dynamic NBTI lifetime model for inverter-like waveform

In this paper, a simple yet accurate NBTI lifetime model has been formulated for a pMOSFET working in dynamic AC condition. The model is based on detailed dynamic NBTI (DNBTI) characterization for inverter-like waveform stress. The fitting parameters of the model can be readily obtained from the calibration of one-time DNBTI lifetime measurement for a small set of frequency/duty cycle matrix. After that, it can be employed to estimate the NBTI lifetime for a pMOSFET under any AC operating condition with reasonably good agreement. Additionally, it is shown that the lifetime enhancement by a shorter duty cycle is even more significant than that by a higher frequency. The application of the model to the lifetime estimation of circuits with multiple operation modes is also discussed.