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. (C) 2013 Elsevier Ltd. All rights reserved.