Effect of body bias on negative bias temperature instability in pMOSFET with SiON gate dielectrics

摘要

We evaluated the body bias (V_(bs)) effect on negative bias temperature instability (NBTI) in pMOSFET devices with various channel lengths and channel dopant concentrations for the first time. We found that additional NBTI degradation starts to occur due to substrate hot holes when V_(bs) increases, over a certain transition point. This transition point was dependent on both channel length and channel dopant concentration of the devices. In the pMOSFETs with long channel length and high dopant concentration, even small positive V_(bs) can cause the additional degradation due to large body effect and high initial threshold voltage (V_t), respectively. This observation can resolve the conflicting arguments on whether V_(bs) enhances NBTI degradation or not.