Impact of etch processes on the chemistry and surface states of the topological insulator Bi2Se3

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dc.contributor.authorBarton, Adam T.
dc.contributor.authorWalsh, Lee A.
dc.contributor.authorSmyth, Christopher M.
dc.contributor.authorQin, Xiaoye
dc.contributor.authorAddou, Rafik
dc.contributor.authorCormier, Christopher
dc.contributor.authorHurley, Paul K.
dc.contributor.authorWallace, Robert M.
dc.contributor.authorHinkle, Christopher L.
dc.contributor.funderNational Science Foundationen
dc.contributor.funderHorizon 2020en
dc.contributor.funderScience Foundation Irelanden
dc.date.accessioned2021-11-10T15:57:36Z
dc.date.available2021-11-10T15:57:36Z
dc.date.issued2019-08-15
dc.description.abstractThe unique properties of topological insulators such as Bi2Se3 are intriguing for their potential implementation in novel device architectures for low power and defect-tolerant logic and memory devices. Recent improvements in the synthesis of Bi2Se3 have positioned researchers to fabricate new devices to probe the limits of these materials. The fabrication of such devices, of course, requires etching of the topological insulator, in addition to other materials including gate oxides and contacts which may impact the topologically protected surface states. In this paper, we study the impact of He+ sputtering and inductively coupled plasma Cl2 and SF6 reactive etch chemistries on the physical, chemical, and electronic properties of Bi2Se3. Chemical analysis by X-ray photoelectron spectroscopy tracks changes in the surface chemistry and Fermi level, showing preferential removal of Se that results in vacancy-induced n-type doping. Chlorine-based chemistry successfully etches Bi2Se3 but with residual Se–Se bonding and interstitial Cl species remaining after the etch. The Se vacancies and residuals can be removed with postetch anneals in a Se environment, repairing Bi2Se3 nearly to the as-grown condition. Critically, in each of these cases, angle-resolved photoemission spectroscopy (ARPES) reveals that the topologically protected surface states remain even after inducing significant surface disorder and chemical changes, demonstrating that topological insulators are quite promising for defect-tolerant electronics. Changes to the ARPES intensity and momentum broadening of the surface states are discussed. Fluorine-based etching aggressively reacts with the film resulting in a relatively thick insulating film of thermodynamically favored BiF3 on the surface, prohibiting the use of SF6-based etching in Bi2Se3 processing.en
dc.description.statusPeer revieweden
dc.description.versionAccepted Versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationBarton, A. T., Walsh, L. A., Smyth, C. M., Qin, X., Addou, R., Cormier, R., Hurley, P. K., Wallace R. M., and Hinkle (2019) 'Impact of etch processes on the chemistry and surface states of the topological insulator Bi2Se3', ACS Applied Materials & Interfaces, 11 (35), pp.32144-32150. doi: 10.1021/acsami.9b10625en
dc.identifier.doi10.1021/acsami.9b10625en
dc.identifier.eissn1944-8252
dc.identifier.endpage32150en
dc.identifier.issn1944-8244
dc.identifier.issued35en
dc.identifier.journaltitleACS Applied Materials & Interfacesen
dc.identifier.startpage32144en
dc.identifier.urihttps://hdl.handle.net/10468/12192
dc.identifier.volume11en
dc.language.isoenen
dc.publisherAmerican Chemical Society (ACS)en
dc.relation.projectinfo:eu-repo/grantAgreement/NSF/Directorate for Engineering::Division of Electrical, Communications & Cyber Systems/1802166/US/Collaborative Research: Defect Immune, Topologically Protected Devices for Ultra-Low Power Electronics/en
dc.relation.projectinfo:eu-repo/grantAgreement/EC/H2020::MSCA-COFUND-FP/713567/EU/Cutting Edge Training - Cutting Edge Technology/EDGEen
dc.relation.projectinfo:eu-repo/grantAgreement/SFI/SFI Research Centres/12/RC/2278/IE/Advanced Materials and BioEngineering Research Centre (AMBER)/en
dc.rights© 2019, American Chemical Society. This 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 https://pubs.acs.org/doi/10.1021/acsami.9b10625en
dc.subjectTopological insulatoren
dc.subjectBismuth selenideen
dc.subjectSurface statesen
dc.subjectProcess integrationen
dc.subjectDirac coneen
dc.subjectEtch chemistryen
dc.titleImpact of etch processes on the chemistry and surface states of the topological insulator Bi2Se3en
dc.typeArticle (peer-reviewed)en
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