Characteristics of ZnO thin film transducers deposited by pulsed laser deposition

High quality ZnO thin films for BAW transducers have been deposited on silicon and sapphire substrates by pulsed laser deposition. An Nd:YAG laser (λ=1.06 μm, τ_FWHM=10 ns), able to deliver an output energy of 0.3 J/pulse, was used to irradiate pure Zn targets in an oxygen reactive atmosphere. Characterization of the films as obtained was conducted to establish their performance as a piezoelectric layer in transducers for BAW devices in the gigahertz range. Cross-section Scanning Electron Microscopy and X-ray diffraction studies show good crystallinity and perpendicular c-axis orientation. Insertion loss measurements, electromechanical coupling coefficient values and d₃₃ coefficients are similar, and in some cases superior, to that obtained by more laborious techniques