Application of jet-printed PZT -layers for actuation of small beams, membranes and a 2-dimensional scanning actuator

To close the technological thickness gap between very thin PZT-layer deposition and bulk PZT, a new technology called Jet Printing has been introduced recently, which can be used to deposit layers between 5 and 100 μm thickness. This technology is used for the first time to fabricate bimorph actuator elements suitable for actuation purposes in MEMS. At first, 10 to 40 um thin PZT layers are deposited on beam shaped structures made of 30 um thick steel. This basic actuator beams were stimulated by an AC voltage, and the reflected laser beam showed reasonable dynamic deflection angles of about 5° maximum. Secondly, deposition on anisotropically etched silicon membranes with varying thickness from 25 to 125 um was carried out. It appeared, that at a membrane thickness lower than 50 um technologically effects can break the membrane. However, for membranes thicker than that, direct deposition after anisotropic etching could be applied successfully, and dynamic deflection of this membranes could be proofed by laserinterferometric measurement. Finally, a small structure capable of diverting a laser beam and carrying out two-dimensional scanning was designed and fabricated from 30 um thick steel using laser ablation. The scanner is actuated by four actuator beams, on which 30 μm thick PZT has been Jet Printed as the actuating material. The electrodes on the beams can be stimulated separately, and therefore control the scanning direction. Experiments showed the capability of the structure to be actuated, and deflection angles up to 5° could be measured.