High Piezoelectric Coefficient Ferroelectric Films for MEMS Applications

压电薄膜由于其大的产生力、高的机电耦合系数和可产生的大量电荷输出，在许多MEMS应用中是有吸引力的元件。本提案着重于提高压电MEMS器件性能的两种方法：(i)利用面内极化结构增强薄铁电薄膜的有效压电响应；（ii）开发小型化的屈张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锆钛酸铅薄膜的压电性能如何与穿透厚度极化换向器相比较，以及相对于传统极化薄膜在压电和介电性能老化和疲劳方面的任何差异。一种加工方案，使生产弯曲MEMS换能器也将开发。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，该开关将使用d33系数和屈张驱动机构进行演示。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。微机电系统（MEMS）是采用与集成电路相同的技术生产的小型化设备，尺寸通常从几微米到几毫米不等。这种装置现在广泛应用于喷墨打印机和汽车气囊展开加速度计。许多领域，包括用于床边诊断的小型生物医学仪器，手机等商业电子产品，以及用于检测各种现象（如有毒气体或工业设备即将发生故障）的小型传感器，都将受益于具有更高灵敏度或具有更多工作能力的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。该项目还将在国家重要技术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.