A new stretched-exponential model for NBTI effects in pMOSFETs

Negative bias temperature instability (NBTI) has greatly limited the lifetimes for product lifetime. Traditional degradation models, such as the classic reaction-diffusion (R-D) model, stretched-exponential (S-E) model and R-D saturated model, have been proposed to quantitatively describe it. In this paper, we use both analytical formulations as well as numerical solutions to explore the relations among these models. In addition, we propose a new S-E model for H₂ diffusion. Compared to the previous S-E model, our proposed S-E model, with high accuracy approximation to the R-D model, can be used to explain the NBTI saturation and lower degradation exponent, and is more suitable for the applications of integrated circuit simulation and analysis.