Investigation of nitrogen enhanced NBTI effect using the universal prediction model

Abstract

The impact of nitrogen concentration on the negative bias temperature instability (NBTI) effect in p-MOSFETs with SiON gate dielectrics is investigated in this paper. The universal NBTI model considering the interface state generation and hole-trapping/detrapping mechanisms is used for modeling the nitrogen enhanced NBTI degradation. Increased nitrogen concentration increases the interface trap density and reduces the activation energy. Correspondingly, the critical model parameters such as the hole-capture time constant and the interface state generation rate are modified. The universality of NBTI model is verified by comparing with the measurement data under conditions of different nitrogen concentrations. Based on the universal NBTI model, the impact of nitrogen on interface-state generation and hole-trapping mechanisms are investigated respectively. The result shows that interface-state generation is more sensitive to nitrogen concentration variation than hole-trapping mechanism. Therefore, the nitrogen enhance NBTI degradation in the high frequency circuit is not as significant as that under low frequency or DC operation conditions.