Deposition and characterization of Pb(Zr,Ti)O₃ sol-gel thin films for piezoelectric cantilever beams

PZT thin films of various thickness were deposited on Pt(111)/Ti/SiO ₂/Si(100) substrates by the sol-gel method. A new method to control the crystallographic orientation of the PZT thin films by modifying the coating layers in one annealing cycle is presented in this paper. PZT films with (111) and (100) preferred orientation were obtained using the multi-coating-layer- annealed and the one-coating-layer-annealed sol-gel methods, respectively. The optimized baking and annealing temperatures at 200 and 600 °C were obtained by analyzing the phase transformation of the PZT precursor solution. The effect of film thickness on the microstructures, crystalline phases, and electrical properties of the PZT films was investigated. Compared to the multi-coating-layer-annealed method, the one-coating-layer-annealed method decreases the residual stress of the PZT films. The remanent polarization increases with the thickness of the PZT films. The remanent polarization (P _r) and coercive fields (E_c) of the one-coating-layer- annealed PZT films with 1.6νm thickness are 25.7νCcm^-2 and 59.2kVcm^-1, respectively. New microcantilevers with two PZT piezoelectric elements and three electric electrodes were designed. These structures can be applied to microsensors, microactuators, or versatile devices having both sensing and actuating functions. The cantilevers were successfully fabricated with wet and dry combined bulk micromachining technique.