Leakage current reduction in 80 nm biaxially strained Si nMOSFETs on in-situ doped SiGe virtual substrates

Abstract

We present a comprehensive study of biaxially strained (up to ~3 GPa stress) Si nMOSFETs down to 80 nm gatelength. Well behaved 80 nm devices with expected strain-induced electrical enhancement were demonstrated. Special emphasis was put on investigation of substrate junction leakage and source to drain leakage. In-situ doped wells and channel profiles demonstrated superior substrate junction leakage for the relaxed SiGe substrates compared to conventional implantation. The source to drain leakage in 80 nm devices was effectively reduced by increment of channel doping and rotation of the channel direction.