First observation of FinFET specific mismatch behavior and optimization guidelines for SRAM scaling

Abstract

V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> -mismatch, and thus SRAM scalability, is greatly improved in narrow SOI FinFETs, with respect to planar bulk, because of their undoped channel and near-ideal gate control. We show by simulations and by measurements that in FinFETs, unlike planar bulk, beta-mismatch becomes dominant, leading to radically different SRAM characteristics. By careful process tuning, we demonstrate a substantial reduction in beta-mismatch. We show the impact of this novel mismatch behavior on SRAM performance and yield under various optimization strategies and thereby provide guidelines for SRAM design in a FinFET technology.