Achieving conduction band-edge Schottky barrier height for arsenic-segregated nickel aluminide disilicide and implementation in FinFETs with ultra-narrow fin widths

Abstract

In this letter, we report the impact of incorporating aluminum (Al) in nickel aluminide disilcide (NiSi2-χAlx) on the Schottky-barrier for electrons (φn B) in NiSi2-χAlx/Si contacts for parasitic series resistance reduction. A wide range of Al concentration was investigated, and an optimum value was obtained. Based on the optimum Al concentration, arsenicsegregated NiSi2-χAlχ (As-segregated NiSi2-χAlχ) contacts were shown to achieve conduction band-edge Schottky-barrier heights with φn B = 0.133 eV. This novel As-segregated NiSi2-χAlx contact was integrated in FinFETs with a gate length of 80 nm and a fin width (WFin) of 11 nm, demonstrating improvement in current drivability of 30% over FinFETs with As-segregated NiSi contacts. We show that these ultranarrow fins (WFin = 11 nm) can be fully silicided reliably with NiSi2-χAlx, demonstrating scalability and the smallest fully silicided Si fins reported to date. For these ultra-narrow Si fins, we have successfully alleviated the concerns of parasitic series resistance without the use of selective epitaxial raised source and drain technology. © 2008 IEEE.