Drain current saturation in graphene field-effect transistors at high fields
Poster (konferens), 2018

Development of competitive high frequency graphene field-effect transistors (GFETs) is hindered, first of all, by a zero-bandgap phenomenon in monolayer graphene, which prevents the drain current saturation and limits significantly the GFET power gain. An approach has been proposed to realise the drain current saturation in GFETs without a bandgap formation, but via velocity saturation of the charge carriers at high fields [1]. In this work, we report on the performance of GFETs fabricated using high quality CVD monolayer graphene and modified technology, which reduce the concentration of
traps generating the charge carriers at high fields [2]. Fig. 1 shows typical output characteristics of GFETs with gate length of 0.5 μm. The drain current clearly reveals the saturation trends at high fields, which we associate with the saturation of the carrier velocity, see inset to Fig. 2 [2]. Fig. 2 shows typical measured (extrinsic) transit frequency (fT) and the maximum frequency of oscillation (fmax), which are characteristics of the current and power gain, respectively. Since fT and fmax are proportional to the carrier velocity, they reveal similar saturation behaviour. We analyse the saturation
effects by applying the Fermi-Dirac carrier statistics. The fT and fmax are up to 34 GHz and 37 GHz, respectively, which are highest among those reported so far for the GFETs with similar gate length and comparable with those reported for Si MOSFETs [3].

field-effect transistors

drain current

graphene

high frequency performance

Författare

Marlene Bonmann

Chalmers, Mikroteknologi och nanovetenskap (MC2), Terahertz- och millimetervågsteknik

Andrei Vorobiev

Chalmers, Mikroteknologi och nanovetenskap (MC2), Terahertz- och millimetervågsteknik

Xinxin Yang

Chalmers, Mikroteknologi och nanovetenskap (MC2), Terahertz- och millimetervågsteknik

Muhammad Asad

Chalmers, Mikroteknologi och nanovetenskap (MC2), Terahertz- och millimetervågsteknik

Jan Stake

Chalmers, Mikroteknologi och nanovetenskap (MC2), Terahertz- och millimetervågsteknik

Luca Banszerus

RWTH Aachen University

Christoph Stampfer

RWTH Aachen University

Martin Otto

AMO

Daniel Neumaier

AMO

Pedro C. Feijoo

Universitat Autonoma de Barcelona (UAB)

Francisco Pasadas

Universitat Autonoma de Barcelona (UAB)

David Jiménez

Universitat Autonoma de Barcelona (UAB)

Graphene Week
San Sebastian, Spain,

Kolbaserat höghastighet 3D GaN elektroniksystem

Stiftelsen för Strategisk forskning (SSF), 2014-03-01 -- 2019-06-30.

Flexibla terahertz detektorer i grafen

Vetenskapsrådet (VR), 2018-01-01 -- 2021-12-31.

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2018-12-17