On the Distribution of NBTI Time Constants on a Long, Temperature-Accelerated Time Scale

Recent investigations on individual defects contributing to negative bias temperature instability (NBTI) showed that the emission and capture time constants are thermally activated via an Arrhenius law. We apply this finding to conventional micrometer-sized devices where NBTI is the response of up to millions of defects. We rapidly switch the device temperature using an on-chip heating structure in order to accelerate NBTI stress and recovery and acquire experimental data on an up to 18 decades long time scale. On this extended time scale, we find that the distribution of NBTI defect time constants is log-normal with large mean and variance which follows directly from a normal distribution of energy barriers in Arrhenius law. As such, our work clearly identifies the role of temperature for NBTI and suggests a method for accurate life-time estimations.