High Piezoelectric Coefficient Ferroelectric Films for MEMS Applications

Piezoelectric thin films are attractive elements in several MEMS applications due to

the large generated force, high electromechanical coupling coefficients, and

substantial charge output that can be generated. This proposal focuses on two

approaches to increasing the performance in piezoelectric MEMS devices: (i) enhancing

the effective piezoelectric response in thin ferroelectric films utilizing in-plane

poled structures and (ii) developing miniaturized flextensional transducers to amplify

the piezoelectric effect. From the scientific standpoint, the program will determine

how the piezoelectric properties of in-plane polarized lead zirconate titanate films

compare to through-the-thickness polarized transducers, as well as any differences in

the way piezoelectric and dielectric properties age and fatigue relative to

conventionally poled films. A processing scheme to enable production of flextionsional

MEMS transducers will also be developed. In addition, a MEMS switch for RF applications

with large displacement (~2 microns) and high-speed (

demonstrated using the d33 coefficient and a flextensional actuation mechanism. The

educational aspects of this program will concentrate on training graduate as well as

undergraduate researchers.

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Microelectromechanical systems (MEMS) are miniaturized devices produced with the same

techniques developed for integrated circuits, and typically range from several microns

to several millimeters in size. Such devices are now widely used in ink jet printers

and automobile air bag deployment accelerometers. Many fields, including miniaturized

biomedical instrumentation for bedside diagnosis, commercial electronics such as cell

phones, and small sensors to detect phenomena as diverse as toxic gases or the imminent

failure of a piece of industrial equipment would benefit from MEMS devices with higher

sensitivities or with the capability of doing more work. This program is designed to

increase the functionality of MEMS systems by exploring the integration of high

performance ferroelectric thin films with motion amplification. This program will also

train and educate scientists in an interdisciplinary research environment in a

technologically-significant area of national importance.