Contact Resistance Reduction Technology Using Selenium Segregation for N-MOSFETs With Silicon–Carbon Source/Drain

We report the integration of a novel selenium segregation (SeS) technology in the silicide contact of strained n-MOSFETs featuring silicon-carbon Si_0.99C_0.01 source/drain (S/D) stressors. SeS at the NiSi:C/n-Si_0.99 C_0.01 interface leads to the achievement of low Schottky barrier height and reduced silicide contact resistance R _CSD. At a fixed I _OFF of 100 nA/ mum, the improved silicide contact technology employing SeS contributed to a 20% drive current I _ON enhancement and 30% total series resistance R _Total reduction over control strained devices. The R _Total improvement is primarily due to the reduction of external series resistance R _EXT, which is due to a reduced R _CSD at the NiSi:C/n- Si_0.99C_0.01 interface. Comparable DIBL, V _Tsat and gate leakage density were observed for strained n-MOSFETs with or without the SeS. The impact of introducing Se in the embedded Si_0.99C_0.01 S/D stressor on tensile stress level in the channel region of strained n-MOSFET was also investigated.