Does carrier velocity saturation help to enhance f(max) in graphene field-effect transistors?

dc.contributorAalto-yliopistofi
dc.contributorAalto Universityen
dc.contributor.authorFeijoo, Pedro C.en_US
dc.contributor.authorPasadas, Franciscoen_US
dc.contributor.authorBonmann, Marleneen_US
dc.contributor.authorAsad, Muhammaden_US
dc.contributor.authorYang, Xinxinen_US
dc.contributor.authorGeneralov, Andreyen_US
dc.contributor.authorVorobiev, Andreien_US
dc.contributor.authorBanszerus, Lucaen_US
dc.contributor.authorStampfer, Christophen_US
dc.contributor.authorOtto, Martinen_US
dc.contributor.authorNeumaier, Danielen_US
dc.contributor.authorStake, Janen_US
dc.contributor.authorJimenez, Daviden_US
dc.contributor.departmentDepartment of Electronics and Nanoengineeringen
dc.contributor.groupauthorZhipei Sun Groupen
dc.contributor.groupauthorCentre of Excellence in Quantum Technology, QTFen
dc.contributor.organizationAutonomous University of Barcelonaen_US
dc.contributor.organizationChalmers University of Technologyen_US
dc.contributor.organizationRWTH Aachen Universityen_US
dc.date.accessioned2020-11-06T11:41:00Z
dc.date.available2020-11-06T11:41:00Z
dc.date.issued2020-09-01en_US
dc.description| openaire: EC/H2020/785219/EU//GrapheneCore2 | openaire: EC/H2020/881603/EU//GrapheneCore3
dc.description.abstractIt has been argued that current saturation in graphene field-effect transistors (GFETs) is needed to get optimal maximum oscillation frequency (f(max)). This paper investigates whether velocity saturation can help to get better current saturation and if that correlates with enhancedf(max). We have fabricated 500 nm GFETs with high extrinsicf(max)(37 GHz), and later simulated with a drift-diffusion model augmented with the relevant factors that influence carrier velocity, namely: short-channel electrostatics, saturation velocity effect, graphene/dielectric interface traps, and self-heating effects. Crucially, the model provides microscopic details of channel parameters such as carrier concentration, drift and saturation velocities, allowing us to correlate the observed macroscopic behavior with the local magnitudes. When biasing the GFET so all carriers in the channel are of the same sign resulting in highly concentrated unipolar channel, we find that the larger the drain bias is, both closer the carrier velocity to its saturation value and the higher thef(max)are. However, the highestf(max)can be achieved at biases where there exists a depletion of carriers near source or drain. In such a situation, the highestf(max)is not found in the velocity saturation regime, but where carrier velocity is far below its saturated value and the contribution of the diffusion mechanism to the current is comparable to the drift mechanism. The position and magnitude of the highestf(max)depend on the carrier concentration and total velocity, which are interdependent and are also affected by the self-heating. Importantly, this effect was found to severely limit radio-frequency performance, reducing the highestf(max)from similar to 60 to similar to 40 GHz.en
dc.description.versionPeer revieweden
dc.format.extent8
dc.format.extent4179-4186
dc.format.mimetypeapplication/pdfen_US
dc.identifier.citationFeijoo, P C, Pasadas, F, Bonmann, M, Asad, M, Yang, X, Generalov, A, Vorobiev, A, Banszerus, L, Stampfer, C, Otto, M, Neumaier, D, Stake, J & Jimenez, D 2020, ' Does carrier velocity saturation help to enhance f(max) in graphene field-effect transistors? ', Nanoscale Advances, vol. 2, no. 9, pp. 4179-4186 . https://doi.org/10.1039/c9na00733den
dc.identifier.doi10.1039/c9na00733den_US
dc.identifier.issn2516-0230
dc.identifier.otherPURE UUID: f88b05f4-c058-4a00-b78b-d9b3e1e381e6en_US
dc.identifier.otherPURE ITEMURL: https://research.aalto.fi/en/publications/f88b05f4-c058-4a00-b78b-d9b3e1e381e6en_US
dc.identifier.otherPURE LINK: http://www.scopus.com/inward/record.url?scp=85091198790&partnerID=8YFLogxKen_US
dc.identifier.otherPURE FILEURL: https://research.aalto.fi/files/52536633/Does_carrier_velocity_saturation_help_to_enhance_fmax_in_graphene_field_effect_transistors.pdfen_US
dc.identifier.urihttps://aaltodoc.aalto.fi/handle/123456789/47494
dc.identifier.urnURN:NBN:fi:aalto-202011066386
dc.language.isoenen
dc.publisherRoyal Society of Chemistry
dc.relationinfo:eu-repo/grantAgreement/EC/H2020/881603/EU//GrapheneCore3en_US
dc.relation.ispartofseriesNanoscale Advancesen
dc.relation.ispartofseriesVolume 2, issue 9en
dc.rightsopenAccessen
dc.subject.keywordMAXIMUM OSCILLATION FREQUENCYen_US
dc.subject.keywordSMALL-SIGNAL MODELen_US
dc.subject.keywordFETSen_US
dc.subject.keywordPERFORMANCEen_US
dc.subject.keywordRESISTANCEen_US
dc.subject.keywordPROSPECTSen_US
dc.subject.keywordBANDGAPen_US
dc.subject.keywordPHYSICSen_US
dc.titleDoes carrier velocity saturation help to enhance f(max) in graphene field-effect transistors?en
dc.typeA1 Alkuperäisartikkeli tieteellisessä aikakauslehdessäfi
dc.type.versionpublishedVersion

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