Achieving Conduction Band-Edge Schottky Barrier Height for Arsenic-Segregated Nickel Aluminide Disilicide and Implementation in FinFETs With Ultra-Narrow Fin Widths

摘要

In this letter, we report the impact of incorporating aluminum (Al) in nickel aluminide disilcide $(hbox{NiSi}_{2 - x}hbox{Al}_{x})$ on the Schottky-barrier for electrons $(Phi_{B}^{n})$ in $hbox{NiSi}_{2 - x}hbox{Al}_{x}/hbox{Si}$ 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, arsenic-segregated $hbox{NiSi}_{2 - x}hbox{Al}_{x}$ (As-segregated $hbox{NiSi}_{2 - x}hbox{Al}_{x}$) contacts were shown to achieve conduction band-edge Schottky-barrier heights with $Phi_{B}^{n} = hbox{0.133} hbox{eV}$. This novel As-segregated $hbox{NiSi}_{2 - x}hbox{Al}_{x}$ contact was integrated in FinFETs with a gate length of 80 nm and a fin width $(W_{rm Fin})$ of 11 nm, demonstrating improvement in current drivability of 30% over FinFETs with As-segregated NiSi contacts. We show that these ultranarrow fins $(W_{rm Fin} = hbox{11} hbox{nm})$ can be fully silicided reliably with $hbox{NiSi}_{2 - x}hbox{Al}_{x}$, 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.