Zhou Qifa, Lau Sienting, Wu Dawei, Shung K Kirk
NIH Resource Center for Medical Ultrasonic Transducer Technology, and Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, United States.
Prog Mater Sci. 2011 Feb;56(2):139-174. doi: 10.1016/j.pmatsci.2010.09.001.
Piezoelectric films have recently attracted considerable attention in the development of various sensor and actuator devices such as nonvolatile memories, tunable microwave circuits and ultrasound transducers. In this paper, an overview of the state of art in piezoelectric films for high frequency transducer applications is presented. Firstly, the basic principles of piezoelectric materials and design considerations for ultrasound transducers will be introduced. Following the review, the current status of the piezoelectric films and recent progress in the development of high frequency ultrasonic transducers will be discussed. Then details for preparation and structure of the materials derived from piezoelectric thick film technologies will be described. Both chemical and physical methods are included in the discussion, namely, the sol-gel approach, aerosol technology and hydrothermal method. The electric and piezoelectric properties of the piezoelectric films, which are very important for transducer applications, such as permittivity and electromechanical coupling factor, are also addressed. Finally, the recent developments in the high frequency transducers and arrays with piezoelectric ZnO and PZT thick film using MEMS technology are presented. In addition, current problems and further direction of the piezoelectric films for very high frequency ultrasound application (up to GHz) are also discussed.
压电薄膜最近在各种传感器和致动器设备的开发中引起了相当大的关注，这些设备包括非易失性存储器、可调谐微波电路和超声换能器。本文概述了用于高频换能器应用的压电薄膜的技术现状。首先，将介绍压电材料的基本原理以及超声换能器的设计考虑因素。在综述之后，将讨论压电薄膜的现状以及高频超声换能器开发的最新进展。然后将描述源自压电厚膜技术的材料的制备和结构细节。讨论中包括化学和物理方法，即溶胶 - 凝胶法、气溶胶技术和水热法。还讨论了压电薄膜的电学和压电性能，这些性能对于换能器应用非常重要，例如介电常数和机电耦合系数。最后，介绍了使用MEMS技术的具有压电ZnO和PZT厚膜的高频换能器和阵列的最新进展。此外，还讨论了用于甚高频超声应用（高达GHz）的压电薄膜当前存在的问题和进一步的发展方向。
