On the performance of hafnium-oxide-based negative capacitance FinFETs, with and without a spacer

Abstract

This paper reports a thorough investigation of the impacts of a spacer dielectric on the performance of HfO2-ferroelectric-based negative capacitance (NC)-FinFETs for 10 nm technology (gate length 22 nm) as per International Roadmap for Devices and Systems with in comparison with similarly-sized conventional FinFETs by means of an industry standard technology computer aided design tool. It is found that, although a high-k spacer results in improved subthreshold swing (SS) and I ON, it increases delay due to enhanced gate capacitance for both types of devices. In spite of having higher gate capacitance for a given spacer, the delay is lower for the NC devices than the conventional devices with identical I OFF, which is due to higher I ON in such devices. Comparing with the baseline FinFET; I ON, SS, threshold voltage, delay and power dissipation of NC-FinFET have been found to improve by 69%, 7%, 5%, 14% and 9% respectively, when Si3N4 spacer is used. Implications of spacer on V DD scalability, delay and power dissipation of NC-FinFETs have also been investigated in one-to-one comparison with similarly-sized conventional FinFETs. If identical delay is considered in both the devices, higher active power dissipation due to enhanced gate capacitance is a concern for HfO2-ferroelectric-based NC-FinFETs.