Laser-vibrometric ultrasonic characterization of resonant modes and quality factors of Ge membranes

Oksana Trushkevych, Vishal A. Shah, Maksym Myronov, John E. Halpin, Stephen D. Rhead, Martin J. Prest, David R. Leadley, Rachel S. Edwards

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

The vibrations of a single-crystal germanium (Ge) membrane are studied in air and vacuum using laser vibrometry, in order to determine mechanical properties such as Q-factors, tensile stress, anisotropy, and robustness to shock. Resonance modes up to 3:2 are identified, giving a residual stress measurement of 0.22 GPa, consistent with the value obtained from x-ray relaxation studies. The membrane is found to be isotropic, with Q-factors ranging from around 40 at atmospheric pressure to over 3200 at 5 × 10 -4 mbar, significantly lower than those found in polycrystalline Ge micromechanical devices. The robustness to shock is explained through the high resonance mode frequencies and the dissipation mechanism into the substrate, which is a direct consequence of having a high quality film with low residual tensile stress, giving the potential for such films to be used in optoelectronic devices.

Original languageEnglish
Article number025004
Number of pages13
JournalScience and Technology of Advanced Materials
Volume15
Issue number2
DOIs
Publication statusPublished - 7 Apr 2014

Keywords

  • elastic properties
  • laser interferometry
  • quality factor
  • single crystal Ge membrane

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