Mechanism of thermal atomic layer etch of w metal using sequential oxidation and chlorination: A first-principles study

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dc.check.date2021-07-15
dc.check.infoAccess to this article is restricted until 12 months after publication by request of the publisher.en
dc.contributor.authorKondati Natarajan, Suresh
dc.contributor.authorNolan, Michael
dc.contributor.authorTheofanis, Patrick
dc.contributor.authorMokhtarzadeh, Charles
dc.contributor.authorClendenning, Scott B.
dc.contributor.funderIntel Corporationen
dc.contributor.funderScience Foundation Irelanden
dc.contributor.funderIrish Centre for High-End Computingen
dc.date.accessioned2020-09-29T10:32:37Z
dc.date.available2020-09-29T10:32:37Z
dc.date.issued2020-07-15
dc.date.updated2020-09-29T10:12:37Z
dc.description.abstractThermal atomic layer etch (ALE) of W metal can be achieved by sequential self-limiting oxidation and chlorination reactions at elevated temperatures. In this paper, we analyze the reaction mechanisms of W ALE using the first-principles simulation. We show that oxidizing agents such as O2, O3, and N2O can be used to produce a WOx surface layer in the first step of an ALE process with ozone being the most reactive. While the oxidation pulse on clean W is very exergonic, our study suggests that runaway oxidation of W is not thermodynamically favorable. In the second ALE pulse, WCl6 and Cl2 remove the oxidized surface W atoms by the formation of volatile tungsten oxychloride (WxOyClz) species. In this pulse, each adsorbed WCl6 molecule was found to remove one surface W atom with a moderate energy cost. Our calculations further show that the desorption of the additional etch products is endothermic by up to 4.7 eV. Our findings are consistent with the high temperatures needed to produce ALE in experiments. In total, our quantum chemical calculations have identified the lowest energy pathways for ALE of tungsten metal along with the most likely etch products, and these findings may help guide the development of improved etch reagents.en
dc.description.sponsorshipIntel Corporation; Irish Centre for High-End Computing (project code: tiche081c); Science Foundation Ireland (SFI funded computing cluster at Tyndall National Institute)en
dc.description.statusPeer revieweden
dc.description.versionAccepted Versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationKondati Natarajan, S., Nolan, M., Theofanis, P., Mokhtarzadeh, C. and Clendenning, S. B. (2020) 'Mechanism of Thermal Atomic Layer Etch of W Metal Using Sequential Oxidation and Chlorination: A First-Principles Study', ACS Applied Materials & Interfaces, 12(32), pp. 36670-36680. doi: 10.1021/acsami.0c06628en
dc.identifier.doi10.1021/acsami.0c06628en
dc.identifier.endpage36680en
dc.identifier.issn1944-8244
dc.identifier.issued32en
dc.identifier.journaltitleACS applied materials & interfacesen
dc.identifier.startpage36670en
dc.identifier.urihttps://hdl.handle.net/10468/10599
dc.identifier.volume12en
dc.language.isoenen
dc.publisherAmerican Chemical Societyen
dc.relation.urihttps://pubs.acs.org/doi/10.1021/acsami.0c06628
dc.rights© 2020 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials and 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.0c06628en
dc.subjectAtomic layer etchingen
dc.subjectTransistor contactsen
dc.subjectDensity functional theoryen
dc.subjectSelf-limiting reactionen
dc.subjectAtomistic simulationsen
dc.subjectFirst principlesen
dc.titleMechanism of thermal atomic layer etch of w metal using sequential oxidation and chlorination: A first-principles studyen
dc.typeArticle (peer-reviewed)en
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