Impact of Surface Orientation on the Sensitivity of FinFETs to Process Variations-An Assessment Based on the Analytical Solution of the Schrodinger Equation

Abstract

This paper investigates the impact of surface orientation on V(th) sensitivity to process variations for Si and Ge fin-shaped field-effect transistors (FinFETs) using an analytical solution of the Schrodinger equation. Our theoretical model considers the parabolic potential well due to short-channel effects and, therefore, can be used to assess the quantum-confinement effect in short-channel FinFETs. Our study indicates that, for ultrascaled FinFETs, the importance of channel thickness (t(ch)) variations increases due to the quantum-confinement effect. The Si-(100) and Ge-(111) surfaces show lower V(th) sensitivity to the t(ch) variation as compared with other orientations. On the contrary, the quantum-confinement effect reduces the V(th) sensitivity to the L(eff) variation, and Si-(111) and Ge-(100) surfaces show lower V(th) sensitivity as compared with other orientations. Our study may provide insights for device design and circuit optimization using advanced FinFET technologies.