Novel Nickel-Alloy Silicides 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 ytterbium (Yb) in NiSi to form different NiSi-alloys. Among the NiSi-alloy candidates investigated, it was found that the NiAl-alloy silicide provides the most effective Schottky-barrier height lowering (~250 meV) on n-Si(001) substrates. Integration of NiAl-alloy silicides as the source and drain (S/D) silicide 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 silicide is therefore a promising S/D silicide material for reducing the high parasitic series resistance in narrow fin MuGFETs for enhanced device performance