STP1015

    Ion Beam Deposited Oxide Coatings

    Published: Jan 1988


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    Abstract

    Single-layer coatings of SiO2, Al2O3 and ZrO2 were deposited by ion beam deposition (IBD). IBD is carried out by directing an ion source at a target made of the desired coating material. The material sputtered from the target is directed toward the substrate being coated. The targets chosen for this work were commercially available hot-pressed oxides. To further modify the coating properties, a secondary ion gun was directed toward the substrate to assist the deposition. Thus, ion assisted deposition (IAD) can be combined with IBD. The following coating deposition parameters were varied: composition of the sputter deposition gas mixture, composition of the ion assist gas mixture, and beam voltage and beam current for the ion assist beam. No external heat was applied to the substrates.

    Single-layer ZrO2 coatings were also deposited from a Zr metal target by bombarding this target with an O2:Ar ion beam (Reactive Ion Beam Deposition [RIBD]). These depositions were performed with ion assistance (RIBD/IAD) and without. However, filament life of the ion guns was found to be a problem with these coatings because of the presence of oxygen in the ion beam.

    The refractive indices for all the coatings were determined by ellipsometry at 633 nm. Representative coatings were analyzed by Auger Electron Spectroscopy (AES) to determine stoichiometry and to provide information on the nature and level of impurities. The RMS surface roughness was determined by TIS (Total Integrated Scatter) measurements. In addition, absorption was determined for a few selected coatings from spectral transmission measurements. The influences of ion beam deposition parameters and ion assist-beam parameters on thin film properties of SiO2, Al2O3 and ZrO2 coatings are discussed.

    High reflector coatings at 351 nm were deposited on super-polished substrates utilizing the optimum deposition parameters obtained from the single-layer studies. The reflectors were made from ZrO2 and SiO2 targets. A peak reflectance greater than 99% was achieved.

    Keywords:

    Al, 2, O, 3, ion-beam deposition, ion-beam-assisted deposition, SiO, 2, thin film coatings, ZrO, 2


    Author Information:

    Raj, T
    Martin Marietta Aerospace, Laser Technology Systems, Kirtland Air Force Base, Albuquerque, NM

    Price, JS
    Martin Marietta Aerospace, Laser Technology Systems, Kirtland Air Force Base, Albuquerque, NM

    Carniglia, CK
    Martin Marietta Aerospace, Laser Technology Systems, Kirtland Air Force Base, Albuquerque, NM


    Paper ID: STP18765S

    Committee/Subcommittee: F01.19

    DOI: 10.1520/STP18765S


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