This paper presents optical measurements of the dynamic strain profiles along the tethers of microelectromechanical resonators and relates them to quality factor. Such measurements allow for the quantification of tether dissipation and fair comparison between various tether designs. Our experiments present the first systematic comparison between the best-performing conventional straight-beam tethers with one-dimensional phononic crystal (PnC) tethers for silicon bulk acoustic resonators, and demonstrate more than 3× improvement in mechanical quality factor (Q) when the PnC tethers are used. The spatial decay rate of the mechanical strain profile along the tethers correlates with the measured Q. This work is also the first to demonstrate PnC tethers for electrostatic bulk acoustic resonators, which can be used as pristine, single-material test platforms to better understand intrinsic material loss mechanisms, as well as for ultra-high Q optomechanical resonators.
Conference Dates: January 22-26, 2017
Conference Location: Las Vegas, NV
Conference Title: IEEE International Conference on Micro Electro Mechanical Systems
Pub Type: Conferences
MEMS, microelectromechanical resonator, bulk acoustic resonator, anchor loss, tether, photoelastic