Skip to content
University of Maryland LibrariesDigital Repository at the University of Maryland
    • Login
    View Item 
    •   DRUM
    • Theses and Dissertations from UMD
    • UMD Theses and Dissertations
    • View Item
    •   DRUM
    • Theses and Dissertations from UMD
    • UMD Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    MEMS-Based Silicon Nitride Thin Film Materials and Devices at Cryogenic Temperatures for Space Applications

    Thumbnail
    View/Open
    umi-umd-2260.pdf (8.624Mb)
    No. of downloads: 6243

    Date
    2005-04-13
    Author
    Chuang, Wen-Hsien
    Advisor
    Ghodssi, Reza
    Metadata
    Show full item record
    Abstract
    Microshutter arrays, scheduled to be launched in 2011 as part of NASA's James Webb Space Telescope (JWST), will be the first micro-scale optical devices in outer space using MEMS technology. As the microshutter arrays consist of electrical and mechanical components and must operate in a cryogenic environment reliably over a 10 year mission lifetime, a fundamental challenge for the development of this device is to understand the mechanical behaviors of the micro-scale materials used and the possible failure mechanisms at 30 K. This thesis investigates the mechanical properties and reliability of low-stress LPCVD silicon nitride thin films, the structural materials of the microshutter arrays, at cryogenic temperatures. A helium-cooled cryogenic measurement setup installed inside a focused-ion-beam system is designed, implemented, and characterized to obtain a cryogenic environment down to 20 K. Resonating T-shaped cantilevers with different "milling masses" are used to measure the Young's modulus of silicon nitride thin films, while the fracture strength is characterized by bending tests of these beams. A passive high-sensitivity microgauge sensor based on displacement amplification is introduced to measure residual stress and coefficients of thermal expansion, which are critical for the device performance. To achieve accelerated fatigue study of the microshutter arrays, a novel mechanical-amplifier actuator is designed, fabricated, and tested to emulate their torsional operating stress. Furthermore, nano-scale tensile fatigue tests are demonstrated using similar mechanical-amplifier actuators. The research results of this thesis provide important thin film material parameters for the design, fabrication, and characterization of the microshutter arrays. Moreover, the presented test devices and experimental techniques are not limited for space applications only but can be extended for characterization of other thin film materials used in MEMS and microsystems.
    URI
    http://hdl.handle.net/1903/2399
    Collections
    • Electrical & Computer Engineering Theses and Dissertations
    • UMD Theses and Dissertations

    DRUM is brought to you by the University of Maryland Libraries
    University of Maryland, College Park, MD 20742-7011 (301)314-1328.
    Please send us your comments.
    Web Accessibility
     

     

    Browse

    All of DRUMCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    LoginRegister
    Pages
    About DRUMAbout Download Statistics

    DRUM is brought to you by the University of Maryland Libraries
    University of Maryland, College Park, MD 20742-7011 (301)314-1328.
    Please send us your comments.
    Web Accessibility