FinFET Inverter Designs: Behavior and Challenges of Process Variability

Abstract

Abstract— Technology scaling alongside the increasing process variability impact in modern technology nodes are themain reasons to control deviations over metrics in IC nanome-ter designs. Schmitt Triggers are traditionally used for noise immunity enhancement, and have been recently applied to mitigate radiation effects and process variability impact. The main contribution of this work is to trace the relationship between transistor sizing, supply voltage, and process variability to get a low energy consumption circuit while still keeping low levels of deviations due to the impact of process-induced variability. It is shown that a cost-benefit analysis can highlight sets of sizing and supply voltage where it can provide a 37.51% decrease in energy consumption while only increasing its sensibility by 7.42%. Furthermore, it is presented that the dependence of supply voltage and sensibility to process variability is not directly related, with slight decreases in the supply volt-ages bringing better results. Overall, the traditional CMOS inverter is still the fastest and most energy-efficient circuit, although, when comparing noise immunity characteristics, the 6-Transistor Schmitt Trigger presents higher noise margins, slopes, gains, and hysteresis ratios. The improvements,although, may increase propagation times, energy consumption, and area.