A modified analytical model for AlGaN/GaN FinFETs I – V characteristics

Abstract

In this paper, a high electron mobility transistor’s (HEMT) analytical model, which is based on the vertical operation of Schottky barrier gate, has been modified for the I−V characteristics of rectangular shaped AlGaN/GaN FinFETs having three-sided Schottky barrier gate operation. The proposed model includes the effect of the tri-gate structure on sheet carrier concentration (ns) of the device. A three dimensional Poisson equation is solved keeping in view, the device geometry and applied potentials, to get the effect of the side gates on ns. It is demonstrated that ns of a FinFET depletes relatively faster than its HEMT counterpart due to the extra fields caused by the side gates. Knowing bias dependent ns, FinFET I−V expressions are developed and tested on AlGaN/GaN FinFETs of varying gate lengths (Lg = 0.4 – 1.0 μm) for the above threshold regime. A good agreement between the experimental and modeled characteristics is observed, which demonstrates the validity of the proposed model in predicting the DC characteristics of tri-gate AlGaN/GaN FinFETs.