AVS 63rd International Symposium & Exhibition
    MEMS and NEMS Friday Sessions
       Session MN+MS-FrM

Invited Paper MN+MS-FrM10
Influence of Radiation on MEMS Oscillators

Friday, November 11, 2016, 11:20 am, Room 102B

Session: Radiation Effect in Emerging Micro/Nano Structures, Devices, and Systems
Presenter: Bruce Alphenaar, University of Louisville
Authors: B. Alphenaar, University of Louisville
M.L. Alles, Vanderbilt University
H. Gong, Vanderbilt University
P. Deb Shurva, University of Louisville
J.T. Lin, University of Louisville
J.L. Davidson, Vanderbilt University
S. McNamara, University of Louisville
K. Walsh, University of Louisville
W. Liao, Vanderbilt University
R.A. Reed, Vanderbilt University
Correspondent: Click to Email
The beneficial size, weight, and power requirements provided by micro-electromechanical (MEMS) and nanoelectromechanical (NEMS) memory, logic and sensors for systems operating in extreme radiation environments make it essential that the effects of radiation on MEMS/NEMS devices be investigated. Here we report on the influence of radiation on a micro-scale oscillator consisting of a electrostatically driven silicon cantilever fabricated from a silicon-on-insulator wafer. The position of the cantilever is detected by the piezoresisitve change in an asymmetric silicon beam supporting the cantilever. Prior to radiation exposure, the frequency response of the oscillator remains very stable, provided temperature and pressure are kept constant. Four different radiation sources are used, covering a range of excitation energies: 1) UV B (265 nm) photons 2) 10 keV X-rays 3) 0.8 MeV protons and 4) 2.0 MeV protons. Exposure to 10 keV X-rays at 10.5 krads/minute causes the resonant frequency to shift downwards by approximately 0.4 Hz (50 ppm change) following 2.1 Mrads irradiation. Once the X-ray exposure is removed, the device returns to its original state after an annealing time of 10 hours. The long annealing time and a correlation to the silicon resistance change shows that sample heating is not an important factor. A comparison to UV B results suggests that the frequency shift is related to charge accumulation in the silicon cantilever. Exposure to 0.8 MeV shows permanent change to the resonant frequency suggesting that displacement damage has occurred. This work was funded by the Defense Threat Reduction Agency under contract HDTRA-15-1-0027.