FinFET With Encased Air-Gap Spacers for High-Performance and Low-Energy Circuits

We experimentally demonstrate n-channel bulk FinFET with encased air-gap spacers. Encased air gap in the spacer region is formed by depositing carbon sidewalls, encasing them with silicon nitride (SiN) film and finally removing carbon using mild oxygen plasma. We show that the drive current of air-spacer FinFET is improved by about 40% compared with the baseline bulk FinFET with SiN spacers likely due to enhanced tensile stress in the channel. The parasitic capacitance and ring oscillator delay of FinFET with air-spacers is about 25% and 40% lower compared with that with SiN spacers.