Characterization and Modeling of Hot Carrier-Induced Variability in Subthreshold Region

We developed an analytical model that is able to predict the evolution of the subthreshold slope variability associated with hot carrier (HC) stress. The model assumes that HC stress generates interface states with a Poisson distribution and that the number of HC-induced interface states increases linearly with the HC-induced subthreshold slope variation. We validate the model by means of extensive variability data sets collected on n-channel MOSFETs in 45- and 65-nm CMOS technologies. Furthermore, we investigate the correlation between the threshold voltage and the subthreshold slope fluctuations in order to fully characterize their impact on the subthreshold current variability.