Design, modeling and optimization of a piezoelectric pressure sensor based on thin-film PZT diaphragm contain of nanocrystalline powders

In this paper fabrication of a 0-3 ceramic/ceramic composite lead zirconate titanate, Pb(Zr_0.52Ti_0.48)O₃ thin film has been presented and then a pressure sensor based on multilayer thin-film PZT diaphragm contain of lead zirconate titanate nanocrystalline powders was designed, modeled and optimized. This multilayer diaphragm in general acts as sensor or actuator. ANSYS was used for simulation of diaphragm. Dynamics characteristics of this multilayer diaphragm have been investigated. By this simulation the effective parameters of the multilayer PZT diaphragm for improving the performance of a pressure sensor in different ranges of pressure are optimized. The optimized thickness ratio of PZT layer to SiO₂ was given in the paper to obtain the maximum deflection of the multilayer thin-film PZT diaphragm. A 0-3 ceramic/ceramic composite lead zirconate titanate, Pb(Zr_0.52Ti_0.48)O₃ film has been developed to fabricate the pressure sensor by a hybrid sol gel process. PZT nanopowders fabricated via conventional sol gel method and uniformly dispersed in PZT precursor solution by an attrition mill. Preparing of precursor started from 2-methoxyethanol as a solvent and acetylacetone (acac) as a chelating agent. The resulting composite solution deposited onto platinized silicon by spin coating, pyrolysis at 380degC and annealed at 650degC for 30 minutes, respectively. XRD analysis shows that perovskite structure would be formed due to the presence of a significant amount of ceramic nanopowders. This texture has a good effect on piezoelectric properties of perovskite structure. The film forms a strongly bonded network and less shrinkage occurs, so the films do not crack during process. Also the aspect ratio through this process would be increased. SEM micrographs indicated that PZT films were uniform, crack free and have a composite microstructure.