Electromechanical Characterization of MEMS Materials at Cryogenic
   Temperatures Using a Focused Ion Beam (FIB)


   Collaborators
   Research Overview
    The James Webb Space Telescope (JWST) is being developed at NASA Goddard Space Flight Center, to determine the origin of the galaxies. To accomplish this, the JWST needs a Multi-object Spectrometer (MOS) for Near Infrared (NIR) observations. Two-dimensional microshutter arrays, functioning as object selection devices inside the MOS, are designed for the transmission of light with high efficiency and high contrast. In space, flight equipment has to work for longer durations at cryogenic temperatures without possibility of human intervention. Therefore emphasis on reliability and electromechanical properties are crucial in their development. A new type of test device is proposed to obtain the electromechanical properties of microshutter devices. To simulate outer space environment, a cryogenic measurement setup is installed inside a focused-ion-beam (FIB) system which can provide SEM imaging and mask-less ion milling. The proposed techniques and measuremenet setup can be extended to characterize a serial of MEMS materials from room to cryogenic temperatures.

   Thesis
    W. H. Chuang, "MEMS-based Silicon Nitride Thin Film Materials and Devices at Cryogenic Temperatures for Space Applications Ph.D. Thesis, University of Maryland, College Park, MD, March 2005.

   Journal Papers
   Conference Papers
    W.H. Chuang, R. Fettig, and R. Ghodssi, "Fatigue Study of Nano-scale Silicon Nitride Thin Films Using A Novel Electrostatic Actuator," The 13th International Conference on Solid-State Sensors, Actuators, and Microsystems (Transducers '05), Seoul, Korea, June 5 - 9, 2005.

    W.H. Chuang, R. Fettig, and R. Ghodssi, "High-Cycle Fatigue Testing of Micro/nano-Scale Silicon Nitride Thin Films Using a Novel Mechanical-Amplifier Actuator," Materials Research Society 2005 Spring Meeting, San Francisco, CA, March 28-April 1, 2005.

    W. H. Chuang, R. Fettig and R. Ghodssi, "FIB-Based Cryogenic Characterization and Testing of Silicon Nitride Thin Film Materials and Devices for Space Applications, Proceedings of the Materials Research Society 2004 Fall Meeting, Boston, November 29 - December 3, 2004.

    W. H. Chuang, T. Luger, R. Fettig and R. Ghodssi, "Mechanical Property Characterization of Thin Film Materials for Space Applications," IVC16, The 16th International Vacuum Congress, Venice, Italy, June 28-July 2, 2004.

    W. H. Chuang, T. Luger, R. Fettig and R. Ghodssi, "Characterization of Mechanical Properties of Silicon Nitride Thin Films for Space Applications," Proceedings of Materials Research Society 2003 Fall Meeting, Boston, Devember 1-5, 2003.

    W. H. Chuang, T. Luger, R. Fettig and R. Ghodssi, "Measurement of Mechanical Properties of Silicon Nitride Thin Film at Cryogenic Temperatures," American Vacuum Society 50th International Symposium, Baltimore, Maryland, November 2-7, 2003.