An Expandable Liner Stressor for N-Channel FinFETs

We report the demonstration of a novel ZnS-SiO₂ liner stressor to enhance drive current in Si n-channel FinFETs (N-FinFETs). ZnS-SiO₂ expands during thermal anneal due to an increase in crystallite size. A ZnS-SiO₂ liner stressor wrapping around an N-FinFET can be expanded and made to exert high tensile stress in the N-FinFET channel for drive current enhancement. Saturation drain current enhancement of ~26% and linear drain current enhancement of ~48% were observed for FinFETs with ZnS-SiO₂ liner stressor compared with control FinFETs without ZnS-SiO₂, with no compromise on short-channel effects. The drain current enhancement increases with decreasing gate length. This technology was realized in FinFETs with silicon-carbon source/drain stressors and Al-incorporated NiSi contacts. ZnS-SiO₂ liner stressor could be a strain engineering option for N-FinFETs at sub-20-nm technology nodes.