Pulsed Laser Deposition of Piezoelectric Films for Micro-Fluidic Applications

AbtractThick films of piezoelectric materials have been grown by pulsed laser deposition (PLD) for use in the development of a programmable micro-fluidic controller. ZnO and BaTiO3 (BTO) films were deposited onto various substrates, including Au/Cr coated Si, Pt/Ti coated Si, and Au/Pd coated glass microchannel plates, at substrate temperatures from room temperature to 800 °C in a background pressure of O2 from 3 to 350 mTorr. ZnO films (∼5 µm thick) were single phase and (001) oriented. BTO films, 33 µm thick, on Pt/Ti/Si were single phase and polycrystalline. To fabricate piezoelectric acoustic transducer, an array of 2 × 4 gold electrodes was deposited onto the thick BTO films through a shadow mask by PLD. The transducers were attached to a simple fluidic circuit with a 1.6 × 1.6 mm cross section and used to generate a flow velocity of 1 mm/s at an operating frequency of 50 MHz.