Ca and La-modified lead titanate sol-gel thin films by UV-assisted processing for piezoelectric sensors

A diol-based sol-gel method was used to prepare UV sensitive precursor solutions in the processing of modified lead titanate ferroelectric thin films. Films were deposited by spin-coating onto platinized Si-based substrates. A <111> preferential orientation was promoted by appropriated choice of the substrate and multiple deposition and crystallization steps. Processing under UV radiation was carried out in a novel RTP equipment including an arrangement of high intensity UV excimer lamps. To obtain the desired ferroelectric perovskite structure, moderate temperatures and times were required, with respect to those of the processing without UV irradiation. XRD measurements were carried out to determine the degree of orientation of the films. Ferroelectric characterization was made to investigate the optimum poling conditions of the films. Piezoelectric coefficients, e 31 and d 33 , were determined in order to evaluate the feasibility of the use of the films in piezoelectric sensors.