A Modeling Framework for NBTI Degradation Under Dynamic Voltage and Frequency Scaling

A modeling framework is proposed to predict the degradation and recovery of threshold voltage shift (ΔV
_T
) due to negative bias temperature instability. Double interface reaction- diffusion model with transient trap occupancy model is used to predict the generation and recovery of interface traps (ΔV
_IT
). Empirical stretched exponential equations are used to capture hole trapping and detrapping in preexisting traps (ΔV
_HT
). The framework consists of uncoupled contributions from ΔV
_IT
and ΔV
_HT
and is capable of accurately predicting the ultrafast measured ΔV
_T
during dc, arbitrary multicycle dc, ac, and mixed-mode dc-ac stress. It can predict pulse duty cycle and frequency dependence of ac degradation and also dynamic voltage and frequency scaling waveforms encountered in actual circuits.