Development of InAlN HEMTs for space application

dc.check.embargoformatNot applicableen
dc.check.infoNo embargo requireden
dc.check.opt-outNot applicableen
dc.check.reasonNo embargo requireden
dc.check.typeNo Embargo Required
dc.contributor.advisorParbrook, Peter Jamesen
dc.contributor.advisorBarnes, Andrewen
dc.contributor.authorSmith, Matthew D.
dc.contributor.funderIrish Research Councilen
dc.contributor.funderEuropean Space Agencyen
dc.date.accessioned2016-02-05T10:10:53Z
dc.date.available2016-02-05T10:10:53Z
dc.date.issued2016
dc.date.submitted2016
dc.description.abstractThis thesis investigates the emerging InAlN high electron mobility transistor (HEMT) technology with respect to its application in the space industry. The manufacturing processes and device performance of InAlN HEMTs were compared to AlGaN HEMTs, also produced as part of this work. RF gain up to 4 GHz was demonstrated in both InAlN and AlGaN HEMTs with gate lengths of 1 μm, with InAlN HEMTs generally showing higher channel currents (~150 c.f. 60 mA/mm) but also degraded leakage properties (~ 1 x 10-4 c.f. < 1 x 10-8 A/mm) with respect to AlGaN. An analysis of device reliability was undertaken using thermal stability, radiation hardness and off-state breakdown measurements. Both InAlN and AlGaN HEMTs showed excellent stability under space-like conditions, with electrical operation maintained after exposure to 9.2 Mrad of gamma radiation at a dose rate of 6.6 krad/hour over two months and after storage at 250°C for four weeks. Furthermore a link was established between the optimisation of device performance (RF gain, power handling capabilities and leakage properties) and reliability (radiation hardness, thermal stability and breakdown properties), particularly with respect to surface passivation. Following analysis of performance and reliability data, the InAlN HEMT device fabrication process was optimised by adjusting the metal Ohmic contact formation process (specifically metal stack thicknesses and anneal conditions) and surface passivation techniques (plasma power during dielectric layer deposition), based on an existing AlGaN HEMT process. This resulted in both a reduction of the contact resistivity to around 1 x 10-4 Ω.cm2 and the suppression of degrading trap-related effects, bringing the measured gate-lag close to zero. These discoveries fostered a greater understanding of the physical mechanisms involved in device operation and manufacture, which is elaborated upon in the final chapter.en
dc.description.sponsorshipEMBARK initiative, ESA grant 4000104741/11/NL/Cbien
dc.description.statusNot peer revieweden
dc.description.versionAccepted Version
dc.format.mimetypeapplication/pdfen
dc.identifier.citationSmith, M. D. 2016. Development of InAlN HEMTs for space application. PhD Thesis, University College Cork.en
dc.identifier.endpage221en
dc.identifier.urihttps://hdl.handle.net/10468/2257
dc.language.isoenen
dc.publisherUniversity College Corken
dc.rights© 2016, Matthew D. Smith.en
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/3.0/en
dc.subjectTransistorsen
dc.subjectSpaceen
dc.subjectNitridesen
dc.subjectReliabilityen
dc.subjectSemiconductorsen
dc.subjectRadiationen
dc.subjectElectronicsen
dc.thesis.opt-outfalse
dc.titleDevelopment of InAlN HEMTs for space applicationen
dc.typeDoctoral thesisen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePHD (Engineering)en
ucc.workflow.supervisorpeter.parbrook@tyndall.ie
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