dc.contributor.advisor | Bıyıklı, Necmi | |
dc.contributor.author | Dönmez, İnci | |
dc.date.accessioned | 2016-01-08T18:19:31Z | |
dc.date.available | 2016-01-08T18:19:31Z | |
dc.date.issued | 2013 | |
dc.identifier.uri | http://hdl.handle.net/11693/15499 | |
dc.description | Ankara : Materials Science and Nanotechnology Program of Graduate School of Engineering and Science of Bilkent University, 2013. | en_US |
dc.description | Thesis (Master's) -- Bilkent University, 2013. | en_US |
dc.description | Includes bibliographical references leaves 82-89. | en_US |
dc.description.abstract | With the continuing scaling down of microelectronic integrated circuits and
increasing need for three-dimensional stacking of functional layers, novel or
improved growth techniques are required to deposit thin films with high
conformality and atomic level thickness control. As being different from other
thin film deposition techniques, atomic layer deposition (ALD) is based on selflimiting
surface reactions. The self-limiting film growth mechanism of ALD
ensures excellent conformality and large area uniformity of deposited films.
Additionally, film thickness can be accurately controlled by the number of
sequential surface reactions.
Gallium oxide (Ga2O3) thin films were deposited by plasma-enhanced
ALD (PEALD) using trimethylgallium as the gallium precursor and oxygen
plasma as the oxidant. A wide ALD temperature window was observed from
100 to 400 °C, where the deposition rate was constant at ~0.53 Å/cycle. The
deposition parameters, composition, crystallinity, surface morphology, optical
and electrical properties were studied for as-deposited and annealed Ga2O3
films. In order to investigate the electrical properties of the deposited films,
metal-oxide-semiconductor capacitor structures were fabricated for a variety of
film thicknesses and annealing temperatures. Ga2O3 films exhibited decent
dielectric properties after crystallization upon annealing. Dielectric constant was
increased with film thickness and decreased slightly with increasing annealing temperature. As an additional PEALD experiment, deposition parameters of
In2O3 thin films were studied as well, using the precursors of cyclopentadienyl
indium and O2 plasma. Initial results of this experiment effort are also presented.
Accurate thickness control, along with high uniformity and conformality
offered by ALD makes this technique quite promising for the deposition of
conformal coatings on nanostructures. This thesis also deals with the synthesis
of metal oxide nanotubes using organic nanofiber templates. Combination of
electrospinning and ALD processes provided an opportunity to precisely control
both diameter and wall thickness of the synthesized nanotubes. As a proof-ofconcept,
hafnia (HfO2) nanotubes were synthesized using three-step approach:
(i) preparation of the nylon 6,6 nanofiber template by electrospinning, (ii)
conformal deposition of HfO2 on the electrospun polymer template via ALD
using the precursors of tetrakis(dimethylamido)hafnium and water at 200 °C,
and (iii) removal of the organic template by calculation to obtain freestanding
HfO2 nanotubes (hollow nanofibers). When the same deposition procedure was
applied on nanofibers with different average fiber diameters, thinner HfO2 wall
thicknesses were obtained for the templates having smaller diameters due to
insufficient exposure of precursor molecules to saturate their extremely large
surface area. Thus, “exposure mode” was applied to obtain the desired wall
thickness while coating high-surface area nanofibers. We present the
experimental efforts including film deposition parameters, structural, elemental,
and morphological properties of HfO2 nanotubes. | en_US |
dc.description.statementofresponsibility | Dönmez, İnci | en_US |
dc.format.extent | xvi, 89 leaves, illustrations, graphics | en_US |
dc.language.iso | English | en_US |
dc.rights | info:eu-repo/semantics/openAccess | en_US |
dc.subject | Plasma-Enhanced Atomic Layer Deposition | en_US |
dc.subject | Gallium Oxide | en_US |
dc.subject | Indium Oxide | en_US |
dc.subject | Hafnium Oxide | en_US |
dc.subject | Thin Films | en_US |
dc.subject | Nanotubes | en_US |
dc.subject.lcc | TA418.9.T45 D66 2013 | en_US |
dc.subject.lcsh | Thin films--Surfaces. | en_US |
dc.subject.lcsh | Nanostructures. | en_US |
dc.subject.lcsh | Layer structure (Solids) | en_US |
dc.subject.lcsh | Metallic oxides. | en_US |
dc.subject.lcsh | Nanotubes. | en_US |
dc.subject.lcsh | Oxide coating. | en_US |
dc.subject.lcsh | Chemical vapor deposition. | en_US |
dc.subject.lcsh | Atomic layer deposition. | en_US |
dc.title | Atomic layer deposition of metal oxide thin films and nanostructures | en_US |
dc.type | Thesis | en_US |
dc.department | Graduate Program in Materials Science and Nanotechnology | en_US |
dc.publisher | Bilkent University | en_US |
dc.description.degree | M.S. | en_US |