Thin film piezoelectrics for MEMS
Thin film piezoelectrics for MEMS
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DOI：
10.1023/b:jecr.0000033998.72845.51
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发表时间：
2004-01-01
影响因子：
1.7
通讯作者：
Muralt, P
中科院分区：
文献类型：
--
作者：
Trolier-McKinstry, S;Muralt, P
薄膜压电材料在微机电系统 (MEMS) 中具有许多优势，因为它可以产生大运动（通常具有低磁滞）、高可用能量密度以及具有宽动态范围和低功耗要求的高灵敏度传感器。本文回顾了该领域的文献，重点讨论了影响可用压电响应幅度的因素。对于 ZnO 和 AlN 等非铁电压电材料，讨论了薄膜取向的重要性。 AlN 的高可用电阻率、与 CMOS 处理的兼容性以及高频常数使其在谐振器应用中特别有吸引力。铁电薄膜具有较高的压电响应，可以使执行器以及高灵敏度传感器以较低的电压运行。在铁电薄膜中，大多数开发的MEMS传感器和执行器都采用锆钛酸铅（PZT）薄膜作为传感器。随机取向的 PZT 薄膜在同形相界处表现出约 - 7 C/m(2) 的压电 e(31, f) 系数。在 PZT 薄膜中，取向、成分、晶粒尺寸、缺陷化学和机械边界条件都会影响观察到的压电系数。在{001}取向菱形扭曲钙钛矿中可以观察到可实现的最高压电响应。据报道，各种此类薄膜的 e(31,f) 系数为 - 12 至 - 27 C/m(2)。
Thin film piezoelectric materials offer a number of advantages in microelectromechanical systems (MEMS), due to the large motions that can be generated, often with low hysteresis, the high available energy densities, as well as high sensitivity sensors with wide dynamic ranges, and low power requirements. This paper reviews the literature in this field, with an emphasis on the factors that impact the magnitude of the available piezoelectric response. For non-ferroelectric piezoelectrics such as ZnO and AlN, the importance of film orientation is discussed. The high available electrical resistivity in AlN, its compatibility with CMOS processing, and its high frequency constant make it especially attractive in resonator applications. The higher piezoelectric response available in ferroelectric films enables lower voltage operation of actuators, as well as high sensitivity sensors. Among ferroelectric films, the majority of the MEMS sensors and actuators developed have utilized lead zirconate titanate (PZT) films as the transducer. Randomly oriented PZT films show piezoelectric e(31, f) coefficients of about - 7 C/m(2) at the morphotropic phase boundary. In PZT films, orientation, composition, grain size, defect chemistry, and mechanical boundary conditions all impact the observed piezoelectric coefficients. The highest achievable piezoelectric responses can be observed in {001} oriented rhombohedrally-distorted perovskites. For a variety of such films, e(31,f) coefficients of - 12 to - 27 C/m(2) have been reported.