Probing interface defects in top-gated MoS2 transistors with impedance spectroscopy

dc.check.date2018-06-26
dc.check.infoAccess to this publication is restricted until 12 months after publication at the request of the publisheren
dc.contributor.authorZhao, Peng
dc.contributor.authorAzcatl, Angelica
dc.contributor.authorGomeniuk, Yuri Y.
dc.contributor.authorBolshakov, Pavel
dc.contributor.authorSchmidt, Michael
dc.contributor.authorMcDonnell, Stephen J.
dc.contributor.authorHinkle, Christopher L.
dc.contributor.authorHurley, Paul K.
dc.contributor.authorWallace, Robert M.
dc.contributor.authorYoung, Chadwin D.
dc.contributor.funderNational Science Foundationen
dc.contributor.funderScience Foundation Irelanden
dc.date.accessioned2017-09-12T08:56:47Z
dc.date.available2017-09-12T08:56:47Z
dc.date.issued2017-06-26
dc.date.updated2017-09-12T08:46:51Z
dc.description.abstractThe electronic properties of the HfO2/MoS2 interface were investigated using multifrequency capacitance–voltage (C–V) and current–voltage characterization of top-gated MoS2 metal–oxide–semiconductor field effect transistors (MOSFETs). The analysis was performed on few layer (5–10) MoS2 MOSFETs fabricated using photolithographic patterning with 13 and 8 nm HfO2 gate oxide layers formed by atomic layer deposition after in-situ UV-O3 surface functionalization. The impedance response of the HfO2/MoS2 gate stack indicates the existence of specific defects at the interface, which exhibited either a frequency-dependent distortion similar to conventional Si MOSFETs with unpassivated silicon dangling bonds or a frequency dispersion over the entire voltage range corresponding to depletion of the HfO2/MoS2 surface, consistent with interface traps distributed over a range of energy levels. The interface defects density (Dit) was extracted from the C–V responses by the high–low frequency and the multiple-frequency extraction methods, where a Dit peak value of 1.2 × 1013 cm–2 eV–1 was extracted for a device (7-layer MoS2 and 13 nm HfO2) exhibiting a behavior approximating to a single trap response. The MoS2 MOSFET with 4-layer MoS2 and 8 nm HfO2 gave Dit values ranging from 2 × 1011 to 2 × 1013 cm–2 eV–1 across the energy range corresponding to depletion near the HfO2/MoS2 interface. The gate current was below 10–7 A/cm2 across the full bias sweep for both samples indicating continuous HfO2 films resulting from the combined UV ozone and HfO2 deposition process. The results demonstrated that impedance spectroscopy applied to relatively simple top-gated transistor test structures provides an approach to investigate electrically active defects at the HfO2/MoS2 interface and should be applicable to alternative TMD materials, surface treatments, and gate oxides as an interface defect metrology tool in the development of TMD-based MOSFETs.en
dc.description.sponsorshipNational Science Foundation (NSF UNITE US/Ireland R&D Partnership for support under NSF-ECCS-1407765); Science Foundation Ireland (under the US-Ireland R&D Partnership Programme Grant SFI/13/US/I2862)en
dc.description.statusPeer revieweden
dc.description.versionAccepted Versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationZhao, P., Azcatl, A., Gomeniuk, Y. Y., Bolshakov, P., Schmidt, M., McDonnell, S. J., Hinkle, C. L., Hurley, P. K., Wallace, R. M. and Young, C. D. (2017) 'Probing Interface Defects in Top-Gated MoS2 Transistors with Impedance Spectroscopy', ACS Applied Materials & Interfaces, 9(28), pp. 24348-24356. doi: 10.1021/acsami.7b06204en
dc.identifier.doi10.1021/acsami.7b06204
dc.identifier.endpage24356en
dc.identifier.issn1944-8244
dc.identifier.issued28en
dc.identifier.journaltitleACS Applied Materials & Interfacesen
dc.identifier.startpage24348en
dc.identifier.urihttps://hdl.handle.net/10468/4682
dc.identifier.volume9en
dc.language.isoenen
dc.publisherAmerican Chemical Societyen
dc.rightsThis document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials & Interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/acsami.7b06204en
dc.subjectElectrical characterizationen
dc.subjectHigh-k dielectricsen
dc.subjectInterface defectsen
dc.subjectMolybdenum disulfide (MoS2)en
dc.subjectTop-gated transistorsen
dc.subjectcapacitance−voltage (C−V)en
dc.titleProbing interface defects in top-gated MoS2 transistors with impedance spectroscopyen
dc.typeArticle (peer-reviewed)en
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