A thorough investigation of MOSFETs NBTI degradation

An overview of evolution of transistor parameters under negative bias temperature instability stress conditions commonly observed in p-MOSFETs in recent technologies is presented. The physical mechanisms of the degradation as well as the different defects involved have been discussed according to a systematic set of experiments with different stress conditions. According to our findings, a physical model is proposed which could be used to more accurately predict the transistor degradation. Finally, the influence of different process splits as the gate oxide nitridation, the nitrogen content, the source/drain implant and poly doping level on the NBTI degradation is investigated and discussed with our present understanding.