Contact resistance reduction technology using selenium egregation for N-MOSFETs with silicon-carbon source/drain

Abstract

We report the integration of a novel selenium segregation (SeS) technology in the silicide contact of strained n-MOSFETs featuring silicon-carbon Si0.99C0.01 source/drain (S/D) stressors. SeS at the NiSi:C/n-Ssi0.99C0.01 interface leads to the achievement of low Schottky barrier height and reduced silicide contact resistance RCSD. At a fixed IOFF of 100 nA μ the improved silicide contact technology employing SeS contributed to a 20% drive current ION enhancement and 30% total series resistance RTotal reduction over control strained devices. The RTotal improvement is primarily due to the reduction of external series resistance REXT, which is due to a reduced RCSD at the NiSi:C/ n- Si0.99C0.01 interface. Comparable DIBL,Tsat and gate leakage density were observed for strained n-MOSFETs with or without the SeS. The impact of introducing Se in the embedded Si0.99C0.01 S/D stressor on tensile stress level in the channel region of strained n-MOSFET was also investigated. © 2009 IEEE.