FinFET parasitic resistance reduction by segregating shallow Sb, Ge and As implants at the silicide interface

This paper reports a new contact technology comprising antimony (Sb) co-implantation and segregation to reduce Schottky barrier height (SBH) and parasitic series resistance for N-FinFETs. Experiments with shallow Sb, Ge and As co-implantation in the source/drain (S/D) regions of SOI FinFET found that all three implant species significantly reduced extrinsic resistance. The Sb implant with a 5e13 cm^-2 dose produced the best result with a 31% reduction of extrinsic resistance and a corresponding I_on increase of 19%. This optimum Sb implant is shown to reduce specific contact resistivity (ρ_c) below 10^-8Ω-cm² by decreasing the SBH and increasing the barrier steepness. Electrostatic control comparable to the reference device indicates no degradation in short channel effects for either Sb, Ge or As. This low ρ_c is promising to address key FinFET scaling issues associated with parasitic series resistance for the 14nm node and beyond.