Simulation of Dynamic NBTI Degradation for a 90nm CMOS Technology

The NBTI effect has become the limiting factor for the reliability of p-MOSFETs in the sub-100nm regime. In this work the dynamic NBTI degradation was systematically investigated for a 90nm p-MOSFET by experiment and simulation. For thin gate oxides stressed at low to medium gate voltages the bulk traps can be neglected and NBTI occurs mainly due to the generation of interface traps. Under this condition the reactiondiffusion model can be applied for the prediction of NBTI degradation. The model parameters were calibrated for NBTI simulations at arbitrary gate voltage, frequency, and duty cycle within a calibrated range. The long-time NBTI degradation was simulated up to 10 years in order to estimate the transistor lifetime under typical chip operation conditions.