High Piezoelectric Coefficient Ferroelectric Films for MEMS Applications

Pennsylvania State Univ University Park, University Park PA

Investigators

Abstract

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 (<1microsecond) will be 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. %%% 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.