Selective phase modulation of NiSi using N-ion implantation for high performance dopant-segregated source/drain n-channel MOSFETs

We have developed a novel dual phase-modulated Ni silicide for Schottky barrier and series resistance reduction in dopant-segregated source/drain (DSS) n-MOSFETs. Using pre-silicide N₂ ⁺ implant (thereafter N-implant), it is possible to selectively form interfacial epitaxial Si-rich NiSi₂, reducing electron Schottky barrier(SB) from 0.7 eV to 0.34 eV while maintaining a low resistive bulk NiSi, at the same silicide formation temperature. Dual phase-modulated NiSi shows enhanced thermal stability up to 750degC, low rhos of 26 muOmegacm and SB modulation Deltaphi_Bn = 0.36 eV (expected 81% reduction in contact resistance R_c). Saturation g_m for phase-modulated N-modulated DSS n-FETs shows 32% improvement over control NiSi with 22% reduction in series resistance R_ext, while still maintaining CMOS integratability.