In the field of micro fluidic and acoustic devices, diaphragm actuators are a topic of interest for high-performance applications such as micro-pumps, synthetic jets, micro-speakers, ultrasonic transducers, deformable mirrors, and micro motors. In this study, we explored new designs for piezoelectric flat-diaphragm actuators exploiting conventional longitudinal and transverse modes as well as a novel shear mode. In addition to analytical/finite-element optimizations and comparison of different structures and electrode shapes, the effect of pre-stress on device performance is investigated. The fabricated diaphragms are demonstrated to be highly competitive compared to previously reported actuators with similar sizes, in terms of generated force (1-15 kPa), deflection (3-40 nL), resonance frequency (15-110 kHz), and sound pressure level (>100 dB). These diaphragms are fundamental to realize ultra-low-power micro-speakers for hearing aids, as well as high-pressure and high-flow micro-pumps for gas chromatography systems.
E. E. Aktakka, R. L. Peterson, K. Najafi, “High-stroke and high-deflection bulk-PZT diaphragm and cantilever micro actuators and effect of pre-stress on device performance” IEEE J. of Microelectromechanical Systems, vol. 23, pp. 438-451, 2014.
E. E. Aktakka, H. Kim, K. Najafi, “Wafer-level fabrication of high performance MEMS using bonded and thinned bulk piezoelectric substrates” 15th International Conference on Solid-State Sensors, Actuators, and Microsystems (Transducers’09), Denver, pp. 849-852, June 2009.