AVS 49th International Symposium
    Microelectromechanical Systems (MEMS) Thursday Sessions
       Session MM-ThA

Paper MM-ThA9
Piezoelectric MEMS for RF Filter Applications

Thursday, November 7, 2002, 4:40 pm, Room C-210

Session: Fabrication, Integration, and Packaging Techniques for MEMS
Presenter: A. Wickenden, U.S. Army Research Laboratory
Authors: A. Wickenden, U.S. Army Research Laboratory
B. Piekarski, U.S. Army Research Laboratory
L. Currano, U.S. Army Research Laboratory
J. Pulskamp, U.S. Army Research Laboratory
R.G. Polcawich, U.S. Army Research Laboratory
E. Zakar, U.S. Army Research Laboratory
R. Piekarz, U.S. Army Research Laboratory
D. Washington, U.S. Army Research Laboratory
J. Conrad, U.S. Army Research Laboratory
M. Dubey, U.S. Army Research Laboratory
Correspondent: Click to Email
Resonator arrays for RF filter devices operating in the GHz frequency range are of interest for lightweight, low power, high precision frequency selection applications. A high quality factor (Q) is required to reduce phase noise and ensure stability against frequency-shifting phenomena. MEMS-based resonator devices offer potential advantages in size, weight, and power consumption over surface wave acoustic wave (SAW) or bulk acoustic resonators currently used for frequency filtering applications. Piezoelectric electromechanical resonator devices should demonstrate advantages over equivalent electrostatic devices for high frequency applications, since they are less sensitive to degraded coupling strength as the device dimensions are reduced.@footnote 1@ Resonant frequency response is determined by both device geometry and materials properties. PZT is attractive for piezoelectric filters due to its high piezoelectric coupling coefficient, although the operating frequency of PZT resonators is limited to the MHz range by the large acoustic time constant of the material. Piezoelectric materials such as aluminum nitride (AlN), zinc oxide (ZnO), and related alloys are of interest because their fast acoustic response times translate to theoretical maximum frequencies of >100 GHz.@footnote 2@ Models are being developed to predict the response of piezoelectric MEMS resonators. These models are currently being validated using PZT resonator devices with beam lengths ranging from 400µm to 20µm, with natural frequencies in the MHz regime. Deviation from standard mechanical models has been observed in the measured response of these devices having lengths less than 50µm. The fabrication, testing, and modeling of piezoelectric PZT resonator devices will be discussed, and the extension of the predictive models to alternate materials systems and submicron geometries for GHz applications will be outlined. @FootnoteText@This work is supported in part by DARPA @footnote 1@D.L. DeVoe, Sensors and Actuators A 88, 263-272 (2001) @footnote 2@A. Ballato, "Micro-electro-acoustic Devices for Wireless Communication," IEEE Sarnoff Symposium on Advances in Wired and Wireless Communications (March 1999)