Variability of FinFET AC parameters: A physics‐based insight

Abstract

This paper presents a fully physics‐based variability analysis of single‐fin double‐gate Metal Oxide Semiconductor FET (MOSFET) AC parameters, without resorting to any approximated quasi‐static analysis based on the variations of the DC drain current or charge. Variations of the AC parameters have been investigated as a function of all the relevant geometrical and physical parameters, with emphasis on the ones affecting the device parasitics, especially important for high‐frequency analog applications. A numerically efficient Green's function technique is applied to reduce the simulation time to a few percent of the time required for standard Monte Carlo–based variability analysis. The Green's function approach especially allows for a deep insight into the so‐called local variability source, highlighting the regions of the device where physical variations most significantly affect the output AC performances and opening the way for possible structure optimization. Although presently implemented in a 2D in‐house software, the technique can be easily exported to standard 3D Technology Computer‐Aided Design (TCAD) tools, eg, for tri‐gate FinFET analysis.