Impact of NBTI Aging on Self-Heating in Nanowire FET

Abstract

This is the first work that investigates the impact of Negative Bias Temperature Instability (NBTI) on the Self-Heating (SH) phenomenon in Silicon Nanowire Field-Effect Transistors (SiNW-FETs). We investigate the individual as well as joint impact of NBTI and SH on pSiNW-FETs and demonstrate that NBTI-induced traps mitigate SH effects due to reduced current densities. Our Technology CAD (TCAD)-based SiNW-FET device is calibrated against experimental data. It accounts for thermodynamic and hydrodynamic effects in 3-D nano structures for accurate modeling of carrier transport mechanisms. Our analysis focuses on how lattice temperature, thermal resistance and thermal capacitance of pSiNW-FETs are affected due to NBTI, demonstrating that accurate self-heating modeling necessitates considering the effects that NBTI aging has over time. Hence, NBTI and SH effects need to be jointly and not individually modeled. Our evaluation shows that an individual modeling of NBTI and SH effects leads to a noticeable overestimation of the overall induced delay increase in circuits due to the impact of NBTI traps on SH mitigation. Hence, it is necessary to model NBTI and SH effects jointly in order to estimate efficient (i.e. small, yet sufficient) timing guardbands that protect circuits against timing violations, which will occur at runtime due to delay increases induced by aging and self-heating.