A Ta/Mo Interdiffusion Dual Metal Gate Technology for Drivability Enhancement of FinFETs

A Ta/Mo interdiffusion dual metal gate technology was successfully introduced to FinFET fabrication. The advantage of the proposed technology was examined by using the gate-first process without a metal-etch off step. The Ta/Mo gated nMOS FinFET with a reduced threshold voltage $(V_{\rm th})$ and the Mo gated pMOS FinFET exhibited symmetrical values of $V_{\rm th}$ (0.31/$-$0.36 V), which are desirable for the FinFET CMOS circuit operation with enhanced current drivability. It was also confirmed that the Ta/Mo interdiffusion process causes no degradation in the carrier mobility.