Fabrication of Micro Actuator using piezoelectric thin films

Abstract

In this paper we propose hybrid piezoelectric materials composed of thin film PZT on organic layer. It is well-known that the PZT film shows excellent piezoelectric properties and is easy for microfabrication as MEMS devices. However deposition of PZT films need high process temperature as high as 500℃ which makes it difficult to integrate them on flexible organic materials. In this study we prepared PZT films on epitaxial MgO substrates in advance, and then they were glued onto adhesive polyimide layer. Finally the MgO substrates were etched away and the PZT films combined with the polyimide layer could be obtained as the hybrid materials. We have fabricated microactuators for micropumps using this film. The PZT films on the polyimide layer were integrated on Si substrates with microchannel and pressure cavities, and piezoelectric actuation was evaluated using laser Doppler displacement meter. We have observed clear piezoelectric displacement as high as 250nm at 10V, indicating the hybrid piezoelectric materials is useful for the MEMS applications.