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

Paper MM-TuM4
AlN-based MEMS and NEMS Resonator Devices

Tuesday, November 4, 2003, 9:20 am, Room 320

Session: Development and Characterization of MEMS and NEMS Materials
Presenter: A.E. Wickenden, U.S. Army Research Laboratory
Authors: A.E. Wickenden, U.S. Army Research Laboratory
L.J. Currano, U.S. Army Research Laboratory
M. Dubey, U.S. Army Research Laboratory
S. Hullavarad, University of Maryland, College Park
R.D. Vispute, University of Maryland, College Park
Correspondent: Click to Email
Electromechanical resonator devices using piezoelectric aluminum nitride (AlN) actuation are being developed for RF filters operating in the MHz-GHz frequency range. Composite structures are required for these micro- and nanoelectromechanical systems (MEMS, NEMS) devices, which include the piezoelectric film, metal electrode layers, and a flexural layer. AlN film quality is very dependant on the growth technique, and differences in crystallinity impact the subsequent piezoelectric response of the film. We have demonstrated the pulsed laser deposition (PLD) of highly oriented AlN thin films on Pt-terminated composite MEMS/NEMS structures. Characterization by X-ray diffraction demonstrates a FWHM of 0.2°, a ten-fold improvement over sputtered AlN films typically used in this application. Pattern transfer techniques have been developed for these composite device structures at both micro- and nano-scale. Fully released AlN MEMS beam resonator structures have been fabricated and tested. These devices demonstrate strong electromechanical response, with a 500 nm deflection observed in a fixed-fixed beam with a resonant frequency of 250 kHz. Device dimensions for resonant frequencies near 1 GHz are predicted to scale to near one micron in length and hundreds of nanometers in cross-sectional area. Free-standing 200nm wide x 150nm thick x 10µm long AlN beams with aligned metal electrodes have been demonstrated, using direct-write electron beam lithographic patterning techniques. We will present detailed harmonic and modeshape analysis of AlN MEMS resonators in the 0.15-15 MHz frequency spectrum, and highlight current results in the development of AlN NEMS resonators.