Energy optimal sizing of FinFET standard cells operating in multiple voltage regimes using adaptive independent gate control

Abstract

FinFET has been proposed as an alternative for bulk CMOS in the ultra-low power designs due to its more effective channel control, reduced random dopant fluctuation, higher ON/OFF current ratio, lower energy consumption, etc. The characteristics of FinFETs operating in the sub/near-threshold region are very different from those in the strong-inversion region. This paper introduces an analytical transregional FinFET model with high accuracy in both subthrehold and near-threshold regions. The unique feature of independent gate controls for FinFET devices is exploited for achieving a tradeoff between energy consumption and delay, and balancing the rise and fall times of FinFET gates. This paper proposes an effective design framework of FinFET standard cells based on the adaptive independent gate control method such that they can operate properly at all of subthreshold, near-threshold and super-threshold regions. The optimal voltage for independent gate control is derived so as to achieve equal rise and fall times or minimal energy-delay product at any supply voltage level.