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 (n s ) 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 n s . It is demonstrated that n s of a FinFET depletes relatively faster than its HEMT counterpart due to the extra fields caused by the side gates. Knowing bias dependent n s , FinFET I−V expressions are developed and tested on AlGaN/GaN FinFETs of varying gate lengths (L g =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.

Strain relaxation and self-heating effects of fin AlGaN/GaN HEMTs

“…In the previously published work, analytical model [15,16] and standard drift-diffusion model [6,17] have been applied to study electrical behavior of GaN fin HEMTs. The analytical model enables fast physics-based analysis but can hardly describe complicated 3D device structures.…”

A Unified Depletion/Inversion Model for Heterojunction Trigate FinFETs DC Characteristics

“…In Ref. [23], an attempt has been made to present an analytical model for trigate AlGaN/GaN FinFETs which have no oxide layer beneath the gate electrode. Such a device cannot operate at a relatively high forward bias because of high leakage current and, as a result, there is no possibility of inversion layer formation at the oxide-metal interface.…”

“…Therefore, the model presented in Ref. [23] which involves the 2DEG current alone, can predict I − V characteristics under the depletion mode only, but ceases to work when the device operates in the inversion mode.…”