Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2014)
    Thin Films Wednesday Sessions
       Session TF-WeM

Paper TF-WeM8
Barium Oxide Glass Targets for Thin Film Dielectric Material

Wednesday, December 10, 2014, 10:20 am, Room Makai

Session: Thin Film Synthesis and Characterization II
Presenter: John Jones, Air Force Research Laboratory
Authors: C. Stutz, Air Force Research Laboratory
G. Kozlowski, University of Dayton Research Insitute
S. Smith, University of Dayton Research Institute
J. Goldstein, Air Force Research Laboratory
G. Landis, University of Dayton Research Insitute
C. Hollbrook, Air Force Research Laboratory
J. Jones, Air Force Research Laboratory
Correspondent: Click to Email
Barium-rich, alkali free glasses are expected to be useful for high voltage capacitors due to the high energy storage capacity of Barium, the high resistivity of alkali-free glasses, and the possibility of forming a smooth, glassy surface to minimize the surface electric field intensity. To better understand the structure-property relationships in these glasses, we have synthesized 17 samples of eight different compositions ranging from 22% to 48% mol percent BaO, with a constant ratio of SiO2 to B2O3. These samples were studied with Raman and showed a narrow intermediate range (29-32% BaO) that was independent of BaO content between the stressed-rigid elastic phase (24-29% BaO) and the flexible elastic phase (32-48% BaO). The samples were fabricated into 2.5 cm diameter targets for a pulsed laser deposition (PLD) thin film process. They were nominally clear and made from a melt that was poured into a mold. However the targets would break up when exposed to the 248 nm one joule laser and the deposition onto the substrate was negligible. The targets were also annealed at 50 degrees below the glass transition temperature, but this did not help. A new target process was developed that was more involved and instead of pouring the melt into a form it was poured into de-ionized water to be quenched then ground using a mortar and pestle. After grinding the glass was pressed into a pellet and sintered for densification. The new targets were not transparent. Due to the new process the glass targets were able to withstand the 248 nm one joule laser. Also good coverage of the substrate was obtained during PLD growth. We will discuss the characterization of the thin films based on results from atomic force microscopy, x-ray, and Raman spectra. Also impedance spectroscopy will be presented.