Design, Fabrication, and Performance of a Piezoelectric Uniflex Microactuator

• Published in: Journal of microelectromechanical systems Vol. 18; no. 3; pp. 616 - 625
• Main Authors: Kommepalli, H.K.R., Yu, H.G., Muhlstein, C.L., Trolier-McKinstry, S., Rahn, C.D., Tadigadapa, S.A.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.06.2009; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Actuators; Amplification; Applied sciences; Capacitive sensors; Circuit properties; Design engineering; Displacement; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Fabrication; Force control; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Lead zirconate titanate (PZT: hbox{PbZr}_{0.52} \hbox{Ti}_{0.48}\hbox{O}_{3} ); Mathematical models; Mechanical instruments, equipment and techniques; Microactuators; microelectromechanical systems (MEMS); Microfluidics; Micromechanical devices and systems; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Motion control; Physics; Piezoelectric actuators; Piezoelectricity; PZT microactuators; PZT thin films; Radio control; Radio frequency; Strain; Studies; Switches; uniflex actuators; Mechanical clearance; PZT; Boundary condition; Modeling; Lead zirconate titanate (PZT: PbZr; Piezoelectric ceramics; Thin film; O; Ti; uniflex actuators; Piezoelectric actuators; Microvalves; Piezoelectricity; Fluidic control; PZT microactuators; Microelectromechanical device; Piezoelectric sensor; microelectromechanical systems (MEMS); Microactuators; ); Aluminium; Large displacement; Microwave switches; .; Piezoelectric materials; PZT thin films; Force control; Microfluidics
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2009.2015480

Microactuators provide controlled motion and force for applications ranging from radio frequency switches to microfluidic valves. Large amplitude response in piezoelectric actuators requires amplification of the small strain, exhibited by the piezoelectric material, used in the construction of such actuators. This paper studies a uniflex microactuator that combines the strain amplification mechanisms of a unimorph and flexural motion to produce large displacement and blocking force. The design and fabrication of the proposed uniflex microactuator are described in detail. An analytical model is developed with three connected beams and a reflective symmetric boundary condition that predicts actuator displacement and blocking force as a function of the applied voltage. The model shows that the uniflex design requires appropriate parameter ranges, particularly the clearance between the unimorph and aluminum cap, to ensure that both the unimorph and flexural amplification effects are realized. With a weakened joint at the unimorph/cap interface, the model is found to predict the displacement and blocking force for the actuators fabricated in this work.