University of Twente Student Theses


Anything you build on a large scale or with intense passion invites chaos.

Nijland, Maarten (2010) Anything you build on a large scale or with intense passion invites chaos.

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Abstract:Polymer-assisted deposition was introduced as a viable technique to create all sorts of metal oxide thin films. The technique was illustrated to profit from the advantages associated with current chemical solution deposition techniques. At the same time, polymer-assisted deposition was described to remove major drawbacks conventionally associated with this class of deposition methods. Most of these conclusions were based on studies of epitaxial film growth. The applicability of polymer-assisted deposition to form non-epitaxial films had so far not been extensively studied. The formation of polycrystalline SrRuO3 thin films on substrates that could not act as a template during growth, was attempted in this work. Stable polymeric solutions were made containing strontium and ruthenium precursor complexes. These solutions were spin cast and annealed, particularly on oxidized silicon substrates. A standard procedure was developed to create thin films from the solutions. Deviations were made to the procedure in order to gain a better understanding of the film forming processes. The goal of these experiments was to ultimately find a route that could lead to smooth and dense conductive thin films of SrRuO3. The films that resulted from the standard procedure contained protruding parts, that had developed during the thermal treatment. Protrusions of different shape and composition were found on films annealed at 600 oC and 850 oC. X-ray diffraction studies indicated the presence of SrRuO3 in the former case, but did not provide evidence for presence of any phase in the latter case. The various attempts that were made to inhibit the formation of these protrusions and simultaneously create thin films of proper density, composition, and crystallinity, did not have the desired effect. Protrusions are believed to form by nucleation of SrRuO3 crystallites at the substrate surface. The growth of these crystallites is expected to be facilitated by large diffusion lengths in the film, that are the result of simultaneously occurring decomposition events that reduce the film viscosity. The high curvature that these protrusions possess may explain why the crystallites were found unstable at processing temperatures of 850 oC. The results from the various attempts to improve the thin films, demonstrate the challenge to create SrRuO3 thin films on substrates that can not act as template for epitaxial growth (e.g. amorphous substrates).
Item Type:Essay (Master)
Faculty:TNW: Science and Technology
Subject:35 chemistry
Programme:Chemical Engineering MSc (60437)
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