Relevance of non-exponential single-defect-induced threshold voltage shifts for NBTI variability

We report statistical NBTI datasets of nanoscale Si/SiON pMOSFETs. Weibull-distributed single-defect-induced ΔV_th are observed in the NBTI relaxation transients, in contrast with literature reports of exponential distribution. We discuss the (ir)relevance of a correct description of the single-defect-induced ΔV_th steps for describing the total BTI induced ΔV_th distribution. We show that the BTI induced V_th variance can be correctly predicted based on time-zero V_th0-variability only.