A Comparative Study of Different Physics-Based NBTI Models

Different physics-based negative bias temperature instability (NBTI) models as proposed in the literature are reviewed, and the predictive capability of these models is benchmarked against experimental data. Models that focus exclusively on hole trapping in gate-insulator-process-related preexisting traps are found to be inconsistent with direct experimental evidence of interface trap generation. Models that focus exclusively on interface trap generation are incapable of predicting ultrafast measurement data. Models that assume strong correlation between interface trap generation and hole trapping in switching hole traps cannot simultaneously predict long-time dc stress, recovery, and ac stress and cannot estimate gate insulator process impact. Uncorrelated contributions from generation and recovery of interface traps, together with hole trapping and detrapping in preexisting and newly generated bulk insulator traps, are invoked to comprehensively predict dc stress and recovery, ac duty cycle and frequency, and gate insulator process impact of NBTI. The reaction-diffusion model can accurately predict generation and recovery of interface traps for different devices and experimental conditions. Hole trapping/detrapping is modeled using a two-level energy well model.