The influence of solute additions on intrinsic stress in thin films

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dc.contributor Brewer, Luke N.
dc.contributor Genau, Amber
dc.contributor Gupta, Subhadra
dc.contributor Weaver, Mark Lovell
dc.contributor.advisor Thompson, Gregory B. Kaub, Tyler 2018-07-11T16:49:04Z 2018-07-11T16:49:04Z 2018
dc.identifier.other u0015_0000001_0002928
dc.identifier.other Kaub_alatus_0004D_13399
dc.description Electronic Thesis or Dissertation
dc.description.abstract During physical vapor deposition of thin films, strong intrinsic stresses develop during film growth. These stresses along with the film microstructure are typically controlled through altering the film’s processing conditions. A possible technique to predict how processing influences film stress uses a proposed kinetic model for thin film stress evolution, where contributions to the total stress of the film from individual mechanisms can be elucidated. To determine the application space of the model a series of Cu films was sputter deposited under various deposition conditions to fit the intrinsic stress measurements to the model. Pressure and growth rate stress dependence emerged, which fit well with the model predictions. Expanding upon elemental Cu the influence of a solute additions on the intrinsic stress evolution was examined. Utilizing the Cu(Ni) system as the first case study revealed small Ni additions of 5 at. % resulted in increased compressive stress with further Ni additions showing a reduction in the compressive stress. Noting the stress dependence on solute additions two strongly segregating systems Cu(Ag) and Cu(V) were deposited under similar processing parameters to explore the effect of solute mobility on stress. The addition of Ag, the high atomic mobility solute, or V the low atomic mobility solute, both resulted in the alloy films undergoing grain refinement that scaled with solute content. This grain refinement was attributed to solute segregation and was associated with increased tensile stresses in both systems. Noting the role of solutes on stress in these Cu based alloy systems, further study in another alloy system was conducted to determine if similar mechanisms are present. Using W(Ti) the addition of Ti was observed to reduce the compressive stress of W. Upon examination of the microstructure, Ti additions did not alter the film’s grain size, but increased the fraction of low angle grain boundaries. Collectively, these studies demonstrate solute additions can be used to control the residual stresses, specific grain boundary formations, grain sizes and phase transformations in thin films. This indicates that solutes can be used as another processing tool to tune a thin film to the desired microstructure and stress state.
dc.format.extent 150 p.
dc.format.medium electronic
dc.format.mimetype application/pdf
dc.language English
dc.language.iso en_US
dc.publisher University of Alabama Libraries
dc.relation.ispartof The University of Alabama Electronic Theses and Dissertations
dc.relation.ispartof The University of Alabama Libraries Digital Collections
dc.relation.hasversion born digital
dc.rights All rights reserved by the author unless otherwise indicated.
dc.subject.other Materials Science
dc.title The influence of solute additions on intrinsic stress in thin films
dc.type thesis
dc.type text University of Alabama. Dept. of Metallurgical and Materials Engineering Metallurgical Engineering The University of Alabama doctoral Ph.D.

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