AVS 50th International Symposium
    Microelectromechanical Systems (MEMS) Tuesday Sessions
       Session MM-TuM

Paper MM-TuM5
Anchor Optimization for Quality Factor Improvement in Microresonators

Tuesday, November 4, 2003, 9:40 am, Room 320

Session: Development and Characterization of MEMS and NEMS Materials
Presenter: L.J. Currano, U.S. Army Research Laboratory
Authors: L.J. Currano, U.S. Army Research Laboratory
A.E. Wickenden, U.S. Army Research Laboratory
M. Dubey, U.S. Army Research Laboratory
Correspondent: Click to Email
Arrays of microresonators are of considerable interest for low-cost, high precision RF filters. The quality factor (Q) of a resonator is the figure of merit which determines the amount of signal lost from input to output as well as the slope of the cutoff of a bandpass filter. Some of the factors that degrade the quality factor in mechanical resonators are geometry and material properties, thermoelastic noise, and the transduction mechanism.@footnote 1@ Several discussions of the noise and dissipation mechanisms in microresonators have been published.@footnote 2@ One of the most important loss mechanisms is the transmission of mechanical strain energy to the substrate. The magnitude of strain energy transmitted to the substrate can be manipulated by changing the geometry of the interface between device and substrate. The quality factor for similar PZT-based clamped-clamped beam resonator devices has been found to double by changing the geometry of the anchor slightly. New models are necessary for reducing mechanical losses in the simplest resonator structure, a doubly clamped beam. Finite element analysis provides a vehicle for examining the losses due to transmission of strain energy from the resonator into the substrate and a window into some of the design methods that can be used to minimize mechanical losses. A finite element model which calculates the strain energy transmitted to the substrate in a clamped-clamped resonator beam has been devised, and the results show that the losses steadily decrease with anchor width. Results from the model along with results from electrical testing of PZT resonator devices will be presented. @FootnoteText@@footnote 1@A. N. Cleland and M. L. Roukes, "Noise processes in nanomechanical resonators," Journal of Applied Physics, vol. 92 pp 2758, 2002.@footnote 2@J. R. Vig, "Noise in microelectromechanical systems resonators," IEEE Trans. on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 46 pp. 1558, 1999.