The effects of ion-assisted deposition on the mechanical, physical, chemical and optical properties of magnesium fluoride thin films.

Persistent Link:
http://hdl.handle.net/10150/185917
Title:
The effects of ion-assisted deposition on the mechanical, physical, chemical and optical properties of magnesium fluoride thin films.
Author:
Kennemore, Charles Milton, III.
Issue Date:
1992
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:
This dissertation investigates the results of ion assisted deposition (IAD) on various properties of magnesium fluoride thin films deposited on room temperature substrates. MgF₂ films deposited in this manner have increased abrasion resistance and increased adhesion comparable to that found in films deposited at the usual substrate temperature of approximately 300°C. IAD tends to drive the normal high tensile stress of non-IAD films to a more compressive state thereby reducing the overall stress. The IAD MgF₂ films have a higher index of refraction than non-IAD films, as high as 1.41, and the ultraviolet absorption edge in shifted to longer wavelengths beginning about 350 nm but no detectable absorption at visible wavelengths is seen in the films deposited with less than 250 eV bombardment energies. However, at higher IAD energies beginning at approximately 600 eV an absorption band is present in the red end of the visible spectrum making low energy bombardment the parameter of choice. Transmission electron microscopy and X-ray diffraction studies show that the IAD films have a more amorphous-like structure with fewer and smaller crystallites than non-IAD films deposited on either heated or unheated substrates. Rutherford backscattering spectroscopy (RBS) shows the bombarded films have fluorine depletion that roughly scales with the energy of bombardment with F:Mg ratios as low as 1.69 being found. Bombardment by fluorinated compounds, specifically C₂F₆ and SF₆, limit this depletion and in some instances super fluorinate the resulting compound. Additionally, RBS shows that IAD introduces a significant amount of oxygen throughout the film that is unaccountable as water take-up. X-ray photoelectron spectroscopy (XPS) indicates the presence of two compounds of oxygen that are attributed to MgO and Mg(OH)₂ or some oxy-fluoride complex similar to them and it is the introduction of these compounds which provide for the changes in the properties of IAD MgF₂ as compared to non-IAD films of MgF₂.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Dissertations, Academic.; Optics.; Materials science.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Optical Sciences; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Gibson, Ursula J.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleThe effects of ion-assisted deposition on the mechanical, physical, chemical and optical properties of magnesium fluoride thin films.en_US
dc.creatorKennemore, Charles Milton, III.en_US
dc.contributor.authorKennemore, Charles Milton, III.en_US
dc.date.issued1992en_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.abstractThis dissertation investigates the results of ion assisted deposition (IAD) on various properties of magnesium fluoride thin films deposited on room temperature substrates. MgF₂ films deposited in this manner have increased abrasion resistance and increased adhesion comparable to that found in films deposited at the usual substrate temperature of approximately 300°C. IAD tends to drive the normal high tensile stress of non-IAD films to a more compressive state thereby reducing the overall stress. The IAD MgF₂ films have a higher index of refraction than non-IAD films, as high as 1.41, and the ultraviolet absorption edge in shifted to longer wavelengths beginning about 350 nm but no detectable absorption at visible wavelengths is seen in the films deposited with less than 250 eV bombardment energies. However, at higher IAD energies beginning at approximately 600 eV an absorption band is present in the red end of the visible spectrum making low energy bombardment the parameter of choice. Transmission electron microscopy and X-ray diffraction studies show that the IAD films have a more amorphous-like structure with fewer and smaller crystallites than non-IAD films deposited on either heated or unheated substrates. Rutherford backscattering spectroscopy (RBS) shows the bombarded films have fluorine depletion that roughly scales with the energy of bombardment with F:Mg ratios as low as 1.69 being found. Bombardment by fluorinated compounds, specifically C₂F₆ and SF₆, limit this depletion and in some instances super fluorinate the resulting compound. Additionally, RBS shows that IAD introduces a significant amount of oxygen throughout the film that is unaccountable as water take-up. X-ray photoelectron spectroscopy (XPS) indicates the presence of two compounds of oxygen that are attributed to MgO and Mg(OH)₂ or some oxy-fluoride complex similar to them and it is the introduction of these compounds which provide for the changes in the properties of IAD MgF₂ as compared to non-IAD films of MgF₂.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectDissertations, Academic.en_US
dc.subjectOptics.en_US
dc.subjectMaterials science.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineOptical Sciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairGibson, Ursula J.en_US
dc.contributor.committeememberMacleod, H. A.en_US
dc.contributor.committeememberBovard, B.en_US
dc.identifier.proquest9238522en_US
dc.identifier.oclc713041682en_US
All Items in UA Campus Repository are protected by copyright, with all rights reserved, unless otherwise indicated.