Impact of metal nitrides on contact resistivity of metal-interlayer-semiconductor source/drain in sub-14 nm n-type Si FinFET

In this work, a metal nitride interlayer semiconductor (MN-I-S) source/drain (S/D) model is suggested to investigate the effect of titanium nitride (TiN) and tantalum nitride (TaN) on the specific contact resistivity (£_c) of an MN-I-S S/D structure in a sub-14 nm n-type Si FinFET. The work function (WF) variation of TiN and TaN was considered based on a Rayleigh distribution. In this model, an undoped interlayer (undoped-IL) or heavily doped interlayer (n⁺-IL) were included to identify the effect of IL doping on £_c. The structure with an n⁺-IL provides a very low variation in £_c as well as lower £_c values (i.e., ∼4×10^-9 ω· cm²). By using three-dimensional technology computer-aided design (TCAD) simulation, we also investigated the impact of £_c variation on device performance. The MN-I-S S/D with an n⁺-IL showed a higher on-state drive current with highly suppressed variation.