AVS 53rd International Symposium
    MEMS and NEMS Tuesday Sessions
       Session MN-TuM

Paper MN-TuM11
Effects of Tensile Stress and Viscous Damping on the Resonance of Nanomechanical Beams and Cantilevers

Tuesday, November 14, 2006, 11:20 am, Room 2007

Session: Material Aspects of MEMS and NEMS
Presenter: S.S. Verbridge, Cornell University
Authors: S.S. Verbridge, Cornell University
L.M. Bellan, Cornell University
R.B. Reichenbach, Cornell University
J.M. Parpia, Cornell University
H.G. Craighead, Cornell University
Correspondent: Click to Email
Mechanical flexural resonators with cross-sectional dimensions on the scale of 100 nm have been studied. Devices have been fabricated in silicon nitride, covering a wide range of tensile stress values, from 0 to 1200 MPa. It is shown that the devices with the highest stress exhibit the highest frequencies, as well as the highest quality factors, for devices of a given size. The former result is expected based on traditional considerations of stressed vibrating beams, while the latter is more surprising. Quality factors as high as 200,000 have been attained at room temperature and at high vacuum for doubly-clamped nanoresonators, with MHz range frequencies. We will discuss the various loss mechanisms which might contribute to the quality factors exhibited by these resonators, and will show that the high stress state appears to be relieving certain of these mechanisms, resulting in nanoresonators with losses approaching the thermoelastic limit. We will also briefly discuss the operation of these resonators in environments in which viscous damping becomes the dominant loss mechanism, with applications for chemical and biological sensing. Resonators with 100 nm cross-sections and frequencies as high as 100 MHz have been operated in air, as well as viscous liquids including alcohol and water, using an optical drive technique.