High Piezoelectric Coefficient Ferroelectric Films for MEMS Applications

压电薄膜因其发电力大、机电耦合系数高、可产生大量电荷输出等优点而成为MEMS应用中极具吸引力的元件。提出了两种提高压电MEMS器件性能的方法：(I)利用面内极化结构提高铁电薄膜的有效压电响应；(Ii)开发小型化的弯拉换能器来放大压电效应。从科学的角度来看，该计划将确定平面极化的锆钛酸铅薄膜与厚度极化换能器相比的压电性能如何，以及与传统极化薄膜相比，压电和介电性能在老化和疲劳方面的任何差异。还将开发一种能够生产挠性MEMS换能器的加工方案。此外，还将展示一种用于大位移(~2微米)和高速(1微秒)射频应用的MEMS开关，该开关使用D33系数和伸缩驱动机构。该计划的教育方面将集中于培养研究生和本科生研究人员。微电子机械系统(MEMS)是用为集成电路开发的相同技术生产的小型化设备，通常尺寸从几微米到几毫米不等。这种设备现在被广泛用于喷墨打印机和汽车安全气囊展开加速度计。许多领域，包括用于床边诊断的微型化生物医学仪器、手机等商业电子设备，以及用于检测有毒气体或工业设备即将发生故障等各种现象的小型传感器，都将受益于灵敏度更高或能够做更多工作的MEMS设备。该计划旨在通过探索高性能铁电薄膜与运动放大的集成来增加MEMS系统的功能。该计划还将在一个具有重要技术意义的国家重要领域的跨学科研究环境中培训和教育科学家。

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.