Novel nickel-alloy suicides for source/drain contact resistance reduction in N-channel multiple-gate transistors with sub-35nm gate length

Abstract

In this work, we examined the Schottky-Barrier height modulation of NiSi by the incorporation of Aluminum (Al), Titanium (Ti), Erbium (Er), and Yterbium (Yb) in NiSi to form different NiSi-alloys. Among the NiSi-alloy candidates investigated, it was found that the NiAl-alloy suicide provides the most effective Schottky-Barrier height lowering (∼250 meV) on n-Si(001) substrates. Integration of NiAl-alloy suicides as the source and drain (S/D) suicide material for Multiple-Gate transistors (MuGFETs) was explored, and shown to deliver a drive current IDsat enhancement of 34% compared to MuGFETs employing NiSi S/D. We further showed that the novel NiAl-alloy silicidation process is compatible with lattice-mismatched silicon-carbon (SiC) S/D stressors. NiAl-alloy suicide is therefore a promising S/D suicide material for reducing the high parasitic series resistance in narrow fin MuGFETs for enhanced device performance.