On the differences between ultra-fast NBTI measurements and Reaction-Diffusion theory

Abstract

Reaction-Diffusion (R-D) theory, well-known to successfully explain most features of NBTI stress, is perceived to fail in explaining NBTI recovery. Several efforts have been made to understand differences between NBTI relaxation measured using ultra-fast methods and that predicted by R-D theory. Many alternative theories have also been proposed to explain ultra-fast NBTI relaxation, although their ability in predicting features of NBTI stress remains questionable. In this work, a hole-trap/interface-trap (NHT/NIT) separation framework (Fig. 1a) is used to demonstrate that NIT relaxes slower compared to overall NBTI and this NIT relaxation is consistent with R-D theory. The framework also explains, perhaps for the first time, the observed impacts of nitrogen, stress-time, temperature, frequency, duty cycle, etc. on NBTI degradation. In sum, together with NHT, the R-D model governing NIT is shown to explain NBTI stress and recovery features in nitrided gate oxide p-MOSFETs.