Study on a Scaling Length Model for Tapered Tri-Gate FinFET Based on 3-D Simulation and Analytical Analysis

A compact scaling length model for tapered Tri-gate fin field-effect transistors (FinFETs) is presented based on a 3-D simulation and an analytic potential model. Short-channel effects (SCEs) of rectangular FinFETs can be controlled by designing the fin width, fin height, and gate length to satisfy scaling theory. Tapered FinFETs have a fin top width shorter than the fin bottom width, and they show a different dependence of subthreshold behaviors and SCEs compared to rectangular FinFETs. The proposed scaling length model for tapered FinFETs, expressed as a function of fin bottom width, fin height, and tapering angle, is presented based on the 3-D Poisson's equation and a non-Cartesian mesh. The dependence of the subthreshold behaviors of tapered FinFETs calculated with the proposed model is compared with that of rectangular FinFETs. We found that longer fin bottom widths and fin heights of tapered FinFETs can be designed by applying the proposed scaling length model for the scaling parameter.