High drivability and high reliability MOSFETs with non-doped poly-Si spacer LDD structure (SLDD)

Abstract

It was found that a MOSFET with a non-doped poly-Si spacer LDD (SLDD) structure has high current drivability and high reliability in deep submicron regions. The high gate-fringing field effect caused by this spacer introduces lower lateral electric fields and accumulated n/sup -/ regions. The thin SiO/sub 2/ films under the spacer, which vary the gate-fringing field, affect the performance, in particular the hot-carrier effects of the SLDD. Nondoped poly-Si is a good material for this spacer. SLDDs with thin SiO/sub 2/ films (Tsox) varying from 7 to 25 nm under the nondoped poly-Si spacer were investigated. Both the current drivability and the reliability of the SLDD structure strongly depend on Tsox and are better than for the LDD structure with a SiO/sub 2/ spacer (OLDD).<>