Reactive pulsed laser deposition of piezoelectric and ferroelectric thin films

Piezoelectric (ZnO) and ferroelectric (PZT) thin films were deposited on di fferent substrates (Au coated Si, Al2O3, Coming glass etc.) by reactive pul sed laser deposition, by using a pulsed Nd-YAG laser. ZnO films were deposi ted starting from high purity Zn plates while the PZT films were obtained f rom sintered targets, in different deposition conditions. The influence of the process parameters on the physical and chemical properties of the depos ited films was analyzed by SIMS, XPS, XRD, SEM and TEM. XRD analysis showed that the ZnO films were c-axis oriented, while SEM on cross-sections showe d evidence of a columnar structure. On PZT thin films XRD showed evidence o f a crystalline pseudo-perovskite structure with (111) orientation, while s urface and cross-section SEM studies showed evidence of a compact round gra in structure. Electrical measurements on both ZnO and PZT films found good piezoelectric coefficients. The ferroelectric properties of the PZT films h ave been characterized by a Sawyer-Tower circuit. Samples of ZnO and PZT we re selected and employed in the construction of acceleration sensor and bul k acoustic wave (BAW) devices. Results on frequency response and sensitivit y of constructed devices as well as electroacustical characteristics are pr esented and discussed. (C) 1999 Elsevier Science S.A. All rights reserved.