Characterization and application of jet-printed thin PTZ layers for actuation of MEMS

Although piezoelectric thin films are of great interest for actuator application in MEMS, deposition of PZT films with thicknesses between 5 and 100 μm has been hardly possible. It is therefore the goal of this paper, to investigate the properties of PZT-films of this thickness deposited by the recently introduced Jet-Printing System, especially concerning an application in micro actuator devices. First, PZT layers of thicknesses between 5 and 80 μm have been Jet-Printed on different substrates to investigate the compatibility of the deposition method with standard materials used for MEMS (Micro-Electromechanical Systems). The relative dielectric constant of the layers could be determined between 20 and 550, depending on annealing and deposition conditions. Following, on thin (30 to 100 μm thick) beam-shaped steel substrates PZT layers of 10 to 40 μm thickness were deposited. Since the samples showed deformation caused by technology-introduced stress, the stress value is calculated by means of FEM calculation, and methods for avoiding and compensation of the deformation are introduced. Using the beam-shaped samples, for the first time the piezoelectric constant of the Jet-Printed PZT-layer was calculated to 20...3010-¹² C/N from laser measurements of static and quasi-static beam deflection, and therefore piezoelectric actuation capability could be proofed directly.