Revisiting the impact on sub-threshold regions in uniaxially-strained FETs

Abstract

We report that uniaxial strain in silicon FETs results in a significant modification of subthreshold and near threshold characteristics. We show that modulation of the effective mobility in the region of VTH via uniaxial strain is very nearly proportional to that observed at high gate overdrive. Thus current-density-based VTH should be redefined when significant mobility enhancement is achieved. In this paper, we propose a simple correction to account for strain in the definition of current-density threshold voltage. In particular, this correction may be critical in analog designs where absolute Vth are important to overdrive circuits accurately without leakage penalty. Copyright © 2013 by ECS - The Electrochemical Society.