Dual stress capping layer enhancement study for hybrid orientation finFET CMOS technology

Abstract

3D stress in FinFET and tri-gate FET structures induced by a tensile or compressive capping layer is studied via simulation. The classic bulk-Si piezoresistance model is then used to predict the impact on carrier mobilities. A tensile capping layer is expected to provide dramatic enhancements (>100%) in electron mobility for a (100)-sidewall fin with lang100rang current flow, while a compressive capping layer is expected to provide modest enhancement (<25%) in hole mobility for a (110)-sidewall fin with lang110rang current flow. Mobility enhancement will be greater for fins with higher aspect ratio, so that a stressed capping layer is expected to be more effective for enhancing FinFET performance