Nanoscale fissure formation in AlxGa1–xN/GaN heterostructures and their influence on Ohmic contact formation

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dc.contributor.author Smith, Matthew D.
dc.contributor.author Thomson, D.
dc.contributor.author Zubialevich, Vitaly Z.
dc.contributor.author Li, Haoning
dc.contributor.author Naresh-Kumar, G.
dc.contributor.author Trager-Cowan, C.
dc.contributor.author Parbrook, Peter J.
dc.date.accessioned 2018-07-30T10:30:26Z
dc.date.available 2018-07-30T10:30:26Z
dc.date.issued 2017
dc.identifier.citation Smith, M.D., Thomson, D., Zubialevich, V.Z., Li, H., Naresh-Kumar, G., Trager-Cowan, C. and Parbrook, P.J. (2017) 'Nanoscale fissure formation in AlxGa1–xN/GaN heterostructures and their influence on Ohmic contact formation', Physica Status Solidi A - Applications and Materials Science, 214(1), 1600353 (6pp). doi: 10.1002/pssa.201600353 en
dc.identifier.volume 214
dc.identifier.issued 1
dc.identifier.startpage 1
dc.identifier.endpage 6
dc.identifier.issn 1862-6300
dc.identifier.uri http://hdl.handle.net/10468/6511
dc.identifier.doi 10.1002/pssa.201600353
dc.description.abstract Nanoscale surface fissures on AlxGa1-xN/GaN (15nm/1 mu m) heterostructures grown by metalorganic vapour phase epitaxy (MOVPE) were imaged using tapping-mode atomic force microscopy (AFM) and electron channelling contrast imaging (ECCI). Fissure formation was linked to threading dislocations, and was only observed in samples cooled under H-2 and NH3, developing with increasing barrier layer Al content. No strain relaxation was detected regardless of fissure formation up to barrier layer Al composition fractions of x=0.37. A reduction of measured channel carrier density was found in fissured samples at low temperature. This instability is attributed to shallow trap formation associated with fissure boundaries. For Ti/Al/Ni/Au Ohmic contact formation to high Al content barrier layers, fissures were found to offer conduction routes to the 2DEG that allow for low resistance contacts, with fissure-free samples requiring additional optimisation of the metal stack and anneal conditions to achieve contact resistivity of order those measured in fissured samples. In addition, the effects of fissures were found to be detrimental to thermal stability of sheet and contact resistance, suggesting that fissure formation compromises the integrity of the 2DEG. en
dc.description.sponsorship Engineering and Physical Sciences Research Council (EP/J015792/1); European Regional Development Fund ("INSPIRE") en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher John Wiley & Sons Inc. en
dc.relation.uri https://onlinelibrary.wiley.com/doi/abs/10.1002/pssa.201600353
dc.rights © 2016, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. This is the peer reviewed version of the following article: Smith, M.D., Thomson, D., Zubialevich, V.Z., Li, H., Naresh-Kumar, G., Trager-Cowan, C. and Parbrook, P.J. (2017) 'Nanoscale fissure formation in AlxGa1–xN/GaN heterostructures and their influence on Ohmic contact formation', Physica Status Solidi A - Applications and Materials Science, 214(1), 1600353 (6pp). doi: 10.1002/pssa.201600353, which has been published in final form at https://doi.org/10.1002/pssa.201600353 This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. en
dc.subject Algan en
dc.subject Annealing en
dc.subject Contact resistance en
dc.subject Fissures en
dc.subject High electron mobility transistors en
dc.subject Ohmic contacts en
dc.title Nanoscale fissure formation in AlxGa1–xN/GaN heterostructures and their influence on Ohmic contact formation en
dc.type Article (peer-reviewed) en
dc.internal.authorcontactother Peter James Parbrook, Electrical & Electronic Engineering, University College Cork, Cork, Ireland. +353-21-490-3000 Email: p.parbrook@ucc.ie en
dc.internal.availability Full text available en
dc.description.version Accepted Version en
dc.contributor.funder Engineering and Physical Sciences Research Council
dc.contributor.funder Irish Research Council
dc.contributor.funder European Space Agency
dc.contributor.funder European Regional Development Fund
dc.description.status Peer reviewed en
dc.identifier.journaltitle Physica Status Solidi A - Applications and Materials Science en
dc.internal.IRISemailaddress peter.parbrook@tyndall.ie en
dc.identifier.articleid 1600353


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