Impact of shallow source/drain on the short-channel characteristics of pMOSFET's

We investigated the impact of shallow source/drain (S/D) on the characteris tics of short-channel pMOSFET's with a gate length of 0.1 mu m. We fabricat ed an ultrashallow S/D junction by solid phase diffusion of boron from a BS G sidewall. By precisely estimating the effective channel length, we found that the threshold voltage roll-off is independent of junction depth, In ad dition, the current drivability is degraded in a sample with a shallow junc tion. This makes it clear that a shallow junction with a low surface concen tration does not improve the overall characteristics of ultrasmall pMOSFET' s.