Impact of shallow source/drain on the short-channel characteristics of pMOSFETs

We investigated the impart of shallow source/drain (S/D) on the characteristics of short-channel pMOSFETs with a gate length of 0.1 μm. We fabricated an ultrashallow S/D junction by solid phase diffusion of boron from a BSG sidewall. By precisely estimating the effective channel length, we found that the threshold voltage roll-off is independent of junction depth. In addition, the current drivability is degraded in a sample with a shallow junction. This makes it clear that a shallow junction with a low surface concentration does not improve the overall characteristics of ultrasmall pMOSFETs.