The dependence of the high-frequency performance of graphene field-effect transistors on channel transport properties
Journal article, 2020

This paper addresses the high-frequency performance limitations of graphene field-effect transistors (GFETs) caused by material imperfections. To understand these limitations, we performed a comprehensive study of the relationship between the quality of graphene and surrounding materials and the high-frequency performance of GFETs fabricated on a silicon chip. We measured the transit frequency (fT) and the maximum frequency of oscillation (fmax) for a set of GFETs across the chip, and as a measure of the material quality, we chose low-field carrier mobility. The low-field mobility varied across the chip from 600 cm2/Vs to 2000 cm2/Vs, while the fT and fmax frequencies varied from 20 GHz to 37 GHz. The relationship between these frequencies and the low-field mobility was observed experimentally and explained using a methodology based on a small-signal equivalent circuit model with parameters extracted from the drain resistance model and the charge-carrier velocity saturation model. Sensitivity analysis clarified the effects of equivalent-circuit parameters on the fT and fmax frequencies. To improve the GFET high-frequency performance, the transconductance was the most critical parameter, which could be improved by increasing the charge-carrier saturation velocity by selecting adjacent dielectric materials with optical phonon energies higher than that of SiO2.

high frequency

field-effect transistors

contact resistances

maximum frequency of oscillation

microwave electronics

transit frequency




Muhammad Asad

Chalmers, Microtechnology and Nanoscience (MC2), Terahertz and Millimetre Wave Laboratory

IEEE Journal of the Electron Devices Society

2168-6734 (ISSN)


Carbon Based High Speed 3D GaN Electronics System

Swedish Foundation for Strategic Research (SSF), 2014-03-01 -- 2019-06-30.

Flexibla terahertz detektorer i grafen

Swedish Research Council (VR), 2018-01-01 -- 2021-12-31.

Graphene Core Project 2 (Graphene Flagship)

European Commission (Horizon 2020), 2018-04-01 -- 2020-03-31.

Areas of Advance

Nanoscience and Nanotechnology (2010-2017)

Subject Categories

Physical Sciences

Nano Technology

Other Electrical Engineering, Electronic Engineering, Information Engineering

Driving Forces

Innovation and entrepreneurship


Nanofabrication Laboratory



More information

Latest update

5/7/2020 1