The Efficacy of Metal-Interfacial Layer-Semiconductor Source/Drain Structure on Sub-10-nm n-Type Ge FinFET Performances

We investigate the impact of metal-interfacial layer-semiconductor source/drain (M-I-S S/D) structure with heavily doped n-type interfacial layer (n⁺-IL) or with undoped IL on sub-10-nm n-type germanium (Ge) FinFET device performance using 3-D TCAD simulations. Compared to the metal- semiconductor S/D structure, the M-I-S S/D structures provide much lower contact resistivity. Especially, the M-I-S S/D structure with n⁺-IL provides much lower contact resistivity, resulting in ~5× lower contact resistivity than 1×10^-8 Ω-cm², specified in International Technology Roadmap for Semiconductors. In addition, we found that the M-I-S structure with n⁺-IL remarkably suppresses the sensitivity of contact resistivity to S/D doping concentration.