Optical, chemical and protective properties of thin films produced by ion-assisted deposition.

Persistent Link:
http://hdl.handle.net/10150/185242
Title:
Optical, chemical and protective properties of thin films produced by ion-assisted deposition.
Author:
Cornett, Kenneth D.
Issue Date:
1990
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Magnetooptical data storage materials, such as terbium-iron-cobalt (TbFeCo) alloys are susceptible to pinhole formation, as well as oxidation, particularly of the TB component. Previous studies have shown that oxide overlayers or substrates can be directly reduced by the terbium component. Ultra-thin, partially oxidized samarium films (nominally 5-10 nm) were found to serve as a suitable barrier layer between the TbFeCO film and Al₂O₃ overlayers. Furthermore, the interfacial Sm layer was found to increase the coercivity of the TbFeCo film by nearly a factor of two without degrading the magnetooptic figure of merit or significantly changing its curie point. Ion-assisted deposition (IAD) has been used to alter and improve the protective barrier properties of dielectric materials such as alumina (Al₂O₃) and zirconia (ZrO₂). In particular, pinhole formation in iron films (in lieu of TbFeCo) protected by alumina or zirconia films was greatly affected by the use of ion assisted deposition. In the case of the alumina overlayers, any bombardment was found to improve the protection afforded to underlying iron when the samples were exposed to warm, humid environments. Increasing the intensity of the ion bombardment further improved the quality of the alumina overlayers. The protective properties of zirconia films were excellent when deposited without IAD, but were much more sensitive to the choice of ion bombardment and oxide deposition parameters. Reactive ion-assisted deposition of zirconium oxyfluoride was studied as a potential method for fabricating laterally-graded index profiles in planar waveguides for use in integrated optical devices. For some applications, index changes in excess of 0.2 are required, such as a proposed technique for chromatic aberation compensation of focusing grating couplers. We found waveguide losses in evaporated ZrF₄ films of 5.5 dB/cm at 632.8 nm, and refractive index changes in O₂⁺ bombarded films of 0.23.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Engineering
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Materials Science and Engineering; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Gibson, Ursula J.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleOptical, chemical and protective properties of thin films produced by ion-assisted deposition.en_US
dc.creatorCornett, Kenneth D.en_US
dc.contributor.authorCornett, Kenneth D.en_US
dc.date.issued1990en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractMagnetooptical data storage materials, such as terbium-iron-cobalt (TbFeCo) alloys are susceptible to pinhole formation, as well as oxidation, particularly of the TB component. Previous studies have shown that oxide overlayers or substrates can be directly reduced by the terbium component. Ultra-thin, partially oxidized samarium films (nominally 5-10 nm) were found to serve as a suitable barrier layer between the TbFeCO film and Al₂O₃ overlayers. Furthermore, the interfacial Sm layer was found to increase the coercivity of the TbFeCo film by nearly a factor of two without degrading the magnetooptic figure of merit or significantly changing its curie point. Ion-assisted deposition (IAD) has been used to alter and improve the protective barrier properties of dielectric materials such as alumina (Al₂O₃) and zirconia (ZrO₂). In particular, pinhole formation in iron films (in lieu of TbFeCo) protected by alumina or zirconia films was greatly affected by the use of ion assisted deposition. In the case of the alumina overlayers, any bombardment was found to improve the protection afforded to underlying iron when the samples were exposed to warm, humid environments. Increasing the intensity of the ion bombardment further improved the quality of the alumina overlayers. The protective properties of zirconia films were excellent when deposited without IAD, but were much more sensitive to the choice of ion bombardment and oxide deposition parameters. Reactive ion-assisted deposition of zirconium oxyfluoride was studied as a potential method for fabricating laterally-graded index profiles in planar waveguides for use in integrated optical devices. For some applications, index changes in excess of 0.2 are required, such as a proposed technique for chromatic aberation compensation of focusing grating couplers. We found waveguide losses in evaporated ZrF₄ films of 5.5 dB/cm at 632.8 nm, and refractive index changes in O₂⁺ bombarded films of 0.23.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectEngineeringen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineMaterials Science and Engineeringen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorGibson, Ursula J.en_US
dc.contributor.committeememberZelinski, Brian J.en_US
dc.contributor.committeememberFabes, Brian D.en_US
dc.contributor.committeememberJackson, Kenneth A.en_US
dc.contributor.committeememberPalmer, James M.en_US
dc.identifier.proquest9111929en_US
dc.identifier.oclc710218898en_US
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