A small-signal GFET equivalent circuit considering an explicit contribution of contact resistances

TL;DR

This paper presents a small-signal equivalent circuit model for GFETs that explicitly includes contact resistances, enabling more accurate high-frequency performance analysis and understanding of contact effects on device cutoff frequency.

Contribution

It introduces a methodology to separate contact resistances from intrinsic parameters using de-embedding, improving the accuracy of GFET modeling at high frequencies.

Findings

The model accurately describes high-frequency performance of GFETs.

Contact resistances significantly impact the intrinsic cutoff frequency.

Model parameters scale with device footprint.

Abstract

A small-signal equivalent circuit for graphene field-effect transistors is proposed considering the explicit contribution of effects at the metal-graphene interfaces by means of contact resistances. A methodology to separate the contact resistances from intrinsic parameters, obtained by a de-embedding process, and extrinsic parameters of the circuit is considered. The experimental high-frequency performance of three devices from two different GFET technologies is properly described by the proposed small-signal circuit. Some model parameters scale with the device footprint. The correct detachment of contact resistances from the internal transistor enables to assess their impact on the intrinsic cutoff frequency of the studied devices.