Session 5B-1

Selective Phase Modulation of NiSi using N-ion implantation
for High Performance Dopant-Segregated Source
/Drain n-channel MOSFETs

Abstract

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 0.7eV 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 rs of 26 mΩcm and SB modulation ΔφBn =0.36 eV (expected 81% reduction in contact resistance Rc). Saturation gm for phase-modulated N-modulated DSS n-FETs shows 32% improvement over control NiSi with 22% reduction in series resistance Rext, while still maintaining CMOS integratability.