Numerical simulation of non-uniform interface charge caused by pure bias NBTI degradation in pMOSFETs

Abstract

A simulation method of non-uniform interface charges in pMOSFETs was presented in this paper. By using the 2D device simulation software, it increases the non-uniform interface charges array and calculation module. Bonded with the device negative bias temperature instability NBTI (Negative Bias Temperature Instability) degeneration model, the pure bias NBTI (Pure Drain Bias NBTI) degradation impact on pMOS device threshold voltage was calculated and analyzed. The results show that the pure bias NBTI degradation is smaller than typical NBTI degradation in the beginning of a period of time of the stress, but after prolonged stress, the degradation of both is the same. In the test window, the pure bias NBTI degradation exponent changes along with the gate voltage. These methods and conclusions are helpful for the further analysis of the mechanism of pure bias NBTI degradation and related reliability issues.