AVS 51st International Symposium
    MEMS and NEMS Monday Sessions
       Session MN-MoA

Paper MN-MoA3
Fabrication of Ferroelectric Nanomechanical Resonators

Monday, November 15, 2004, 2:40 pm, Room 213C

Session: Micro and Nano Fabrication Techniques for MEMS and NEMS
Presenter: K. Son, Jet Propulsion Laboratory
Authors: K. Son, Jet Propulsion Laboratory
T. George, Jet Propulsion Laboratory
R.W. Fathauer, Arizona State University
S. Bhaskar, Arizona State University
W. Cao, Arizona State University
S. Dey, Arizona State University
L. Wang, Arizona State University
S.M. Phillips, Arizona State University
B. Lambert, California Institute of Technology
D.P. Weitekamp, California Institute of Technology
B.H. Houston, Naval Research Laboratory
J.F. Vignola, Naval Research Laboratory
J.E. Butler, Naval Research Laboratory
J. Yang, University of South Carolina
M.A. Khan, University of South Carolina
Correspondent: Click to Email
Due to their ultra-small volumes, high sensitivity, and high operating frequencies, nano-mechanical resonators are promising for a variety of applications, including the detection of chemical or biological molecules and RF communications. A major challenge in this technology is efficient coupling to the resonator motion, particularly for applications that preclude low temperatures and/or bulky hardware. We report on our unique approach to this problem, namely the use of a ferroelectric on the resonator. Torsional geometries are used because they are amenable to our coupling technique, whereby an RF voltage applied to metal plates flanking the resonator exerts a torque on the ferroelectric. Due to its large spontaneous polarization, we are using lead zirconate titanate (PZT) as the ferroelectric. PZT is grown on both nanocrystalline diamond and single-crystal GaN resonators using the sol-gel method or MOCVD. Bare Si resonators are also being studied to provide a baseline. Novel double-paddle designs have been developed in which the paddles are supported at nodes of the motion to minimize losses through the supporting members. Their performance is compared to more conventional single-paddle designs. For resonance frequencies in the range of 0.1 to 1.0 GHz, we are examining structures with support-beam cross sections of 200 nm x 200 nm. Resonators are fabricated using electron beam lithography followed by various reactive ion etching methods specifically developed for each material. The sacrificial layers are silicon oxide for both Si and diamond resonators. For GaN, a p-type layer is used for the resonator and an n-type layer for the sacrificial layer. This allows release of the resonators using photoelectrochemical etching. Evaluation of resonators is carried out using scanning laser Doppler vibrometry, and compared to numerical simulations of resonator performance developed using finite element-based structural dynamics codes.