Clamp-Tapering Increases the Quality Factor of Stressed Nanobeams

Mohammad J. Bereyhi, Alberto Beccari, Sergey A. Fedorov, Amir H. Ghadimi, Ryan Schilling, Dalziel J. Wilson, Nils J. Engelsen, Tobias J. Kippenberg

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Stressed nanomechanical resonators are known to have exceptionally high quality factors (Q) due to the dilution of intrinsic dissipation by stress. Typically, the amount of dissipation dilution and thus the resonator Q is limited by the high mode curvature region near the clamps. Here we study the effect of clamp geometry on the Q of nanobeams made of high-stress Si 3 N 4 . We find that tapering the beam near the clamps, thus locally increasing the stress, leads to an increased Q of MHz-frequency low order modes due to enhanced dissipation dilution. Contrary to recent studies of tethered-membrane resonators, we find that widening the clamps leads to a decreased Q despite increased stress in the beam bulk. The tapered-clamping approach has practical advantages compared to the recently developed "soft-clamping" technique, as it enhances the Q of the fundamental mode and can be implemented without increasing the device size.

Original languageEnglish (US)
Pages (from-to)2329-2333
Number of pages5
JournalNano Letters
Issue number4
StatePublished - Apr 10 2019
Externally publishedYes


  • Nanomechanical resonators
  • clamp geometry
  • quality factor
  • silicon nitride
  • tapered-clamping

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering


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