First principles modelling of nucleation and growth during atomic layer deposition onto III-V substrates

Simple item page
dc.check.embargoformatE-thesis on CORA onlyen
dc.check.entireThesisEntire Thesis Restricted
dc.check.opt-outNot applicableen
dc.check.reasonThis thesis is due for publication or the author is actively seeking to publish this materialen
dc.contributor.advisorElliott, Simon D.en
dc.contributor.authorKlejna, Sylwia
dc.contributor.funderScience Foundation Irelanden
dc.date.accessioned2014-02-05T15:04:01Z
dc.date.available2015-02-06T05:00:05Z
dc.date.issued2013
dc.date.submitted2013
dc.description.abstractAtomic layer deposition (ALD) is now used in semiconductor fabrication lines to deposit nanometre-thin oxide films, and has thus enabled the introduction of high-permittivity dielectrics into the CMOS gate stack. With interest increasing in transistors based on high mobility substrates, such as GaAs, we are investigating the surface treatments that may improve the interface characteristics. We focus on incubation periods of ALD processes on III-V substrates. We have applied first principles Density Functional Theory (DFT) to investigate detailed chemistry of these early stages of growth, specifically substrate and ALD precursor interaction. We have modelled the ‘clean-up’ effect by which organometallic precursors: trimethylaluminium (TMA) or hafnium and titanium amides clean arsenic oxides off the GaAs surface before ALD growth of dielectric commences and similar effect on Si3N4 substrate. Our simulations show that ‘clean-up’ of an oxide film strongly depends on precursor ligand, its affinity to the oxide and the redox character of the oxide. The predominant pathway for a metalloid oxide such as arsenic oxide is reduction, producing volatile molecules or gettering oxygen from less reducible oxides. An alternative pathway is non-redox ligand exchange, which allows non-reducible oxides (e.g. SiO2) to be cleaned-up. First principles study shows also that alkylamides are more susceptible to decomposition rather than migration on the oxide surface. This improved understanding of the chemical principles underlying ‘clean-up’ allows us to rationalize and predict which precursors will perform the reaction. The comparison is made between selection of metal chlorides, methyls and alkylamides precursors.en
dc.description.sponsorshipScience Foundation Ireland (07/SRC/I1172)en
dc.description.statusNot peer revieweden
dc.description.versionAccepted Version
dc.format.mimetypeapplication/pdfen
dc.identifier.citationKlejna, S. 2013. First principles modelling of nucleation and growth during atomic layer deposition onto III-V substrates. PhD Thesis, University College Cork.en
dc.identifier.endpage151
dc.identifier.urihttps://hdl.handle.net/10468/1369
dc.language.isoenen
dc.publisherUniversity College Corken
dc.rights© 2013, Sylwia Klejnaen
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/3.0/en
dc.subjectIII-V substrateen
dc.subjectALD precursoren
dc.subjectHigh-k dielectricsen
dc.subjectReducible oxideen
dc.subjectClean-up effecten
dc.subjectAtomic layer depositionen
dc.subjectMetal alkylamideen
dc.subjectLigand decompositionen
dc.subjectDensity functional theory (DFT)en
dc.subject.lcshChemical vapor depositionen
dc.subject.lcshDensity functionalsen
dc.thesis.opt-outfalse
dc.titleFirst principles modelling of nucleation and growth during atomic layer deposition onto III-V substratesen
dc.typeDoctoral thesisen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD (Science)en
ucc.workflow.supervisorsimon.elliott@tyndall.ie
Files
Original bundle
Now showing 1 - 2 of 2
Thumbnail Image
Name:
abstract.pdf
Size:
8.4 KB
Format:
Adobe Portable Document Format
Description:
Abstract
Thumbnail Image
Name:
thesis_corrected.pdf
Size:
4.51 MB
Format:
Adobe Portable Document Format
Description:
Full Text E-thesis
Download
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
5.62 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Doctoral Theses
Chemistry - Doctoral Theses
College of Science, Engineering and Food Science - Doctoral Theses
Tyndall National Institute - Doctoral Theses