We evaluated the channel length dependence of the negative bias temperature instability in deep-submicrometer p-type metal oxide semiconductor field effect transistors (pMOSFETs) having either a boron- or BF2-implanted source/drain (S/D) and a poly-Si film. We found that long-channel-length (10 mu m) pMOSFETs having a BF2-implanted S/D exhibit a larger negative threshold voltage shift (Delta V-th) than do those having a B-implanted S/D. This phenomenon indicates that fluorine atoms enhance boron diffusion into the gate oxide region, resulting in the increase in fixed-positive oxide charges and the decreased density of interface states. In contrast, the shorter-channel-length device having a BF2-implanted S/D displays a smaller value of Delta V-th than does that possessing a B-implanted S/D. These observations indicate that fluorine atoms not only induce negative interface states but also suppress the positive interface traps that occur during NBTI stressing. (c) 2006 The Electrochemical Society.