Mechanism of dynamic NBTI of pMOSFETs

摘要

The negative bias temperature instability of pMOSFETs is studied. It is found that there is strong frequency dependence of the parameters shift. At a certain high frequency, the threshold voltage shift is only about half of that generated by DC stress. The possible sources of this dependence are explored. An empirical model is established, based on the reduction of fixed oxide charges. This model is further used to explain some observed phenomena.