Characterization of pulsed-laser deposited Pb(Zr,Ti)O3 for piezoelectric thin films devices

In the last years lead zirconate titanate (PZT) thin films have been widely studied for their use in piezoelectric and ferroelectric thin films devices. For many applications it is important to have relatively large film area with homogeneous properties. We prepared PZT thin films by pulsed laser deposition in reactive O₂ atmosphere, by using a Nd:YAG laser (λ=1060 nm, τ_FWHM =10 ns, 0.3 J max. energy/pulse, 10 Hz). Au coated Si(111) substrates were heated at approx. 370°C, while the O₂ atmosphere value was maintained at 0.15 mbar. The targets were sintered PZT ceramics disks with Pb(Zr_0.4Ti_0.6)O₃ composition. The obtained films were tested in different zones by few techniques, like XRD, XPS and local piezoelectric coefficient measurements. XRD analysis shown that the structure of the films in all zones was pseudo-perovskite with (111) orientation, but differences in the crystallographic content and the degree of orientation of zones subjected to plasma flux regions arriving at different angles of incidence on sample surface were found. In the same zones XPS studies were performed by using a non-monochromatic Al Kα X-ray source. Scans of Ti2p, Zr3d, Pb4f, O1s were acquired and information about the chemical bonds formed and the compositions in each zone were obtained. The d₃₃ piezoelectric coefficient was locally measured and correlated with chemical and structural film properties. Samples with homogeneous properties were selected and employed in the construction of acceleration sensor devices. Results on response and sensitivity of constructed devices are presented and discussed