Recent Progress in Materials Issues for Piezoelectric MEMS

• Published in: Journal of the American Ceramic Society Vol. 91; no. 5; pp. 1385 - 1396
• Main Author: Muralt, Paul
• Format: Journal Article
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01.05.2008; Blackwell; Wiley Subscription Services, Inc
• Subjects: Applied sciences; Ceramics; Circuit properties; Electric properties; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Exact sciences and technology; Frequency filters; Materials; Materials science; Micro- and nanoelectromechanical devices (mems/nems); Microelectromechanical systems; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Thin films; Mobile radiocommunication; Mobile phone; Ultrasound imaging; Performance characteristic; Review; Micromachine; Radiofrequency filters; Piezoelectric materials; Piezoelectricity; Miniaturization; Piezoelectric thin films; Microelectromechanical device; Standing wave
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1551-2916.2008.02421.x

Piezoelectric materials play a crucial role in a large number of devices and applications modern society would not like to miss. Mobile phones and ultrasonic imaging are just the most prominent ones. Since two decades, miniaturization of mechanical devices in silicon technology is a major research direction in engineering known under name of MEMS, which stands for micro‐electro‐mechanical systems. Piezoelectricity fits very well into this concept and was expected right from the beginning to play its role in MEMS. The breakthrough was made with RF filters in mobile phones working on the principle of standing thickness waves in AlN films. What counts here is acoustic quality and stability. The force champion among piezoelectric thin film materials, Pb(Zr,Ti)O3 gave more problems in processing, and requires more patience to meet requirements and needs for a mass applications. It seems, however, that the breakthrough is imminent. This article attempts to give an overview of the field, highlighting recent achievements, introduce operation principles, and describe some applications.