Stacking effects on dielectric properties of sol-gel derived Pb(Zr0.53Ti0.47)O3/PbTiO3 thin films

A thin film multilayer structure consisting of Pb(Zr0.53Ti0.47)O3(PZT) and PbTiO3(PT) were fabricated by a sol-gel process. The effects of the number of PZT/PT layers upon microstructure and dielectric characteristics were investigated. For a pure PZT thin layer annealed at 600 °C, the microstructure observed was a rosette type, whereas the insertion of PT interlayers yielded thin films with homogeneous grain distribution regardless of the number of PZT/PT layers. With increasing number of PZT/PT layers, the leakage current density and coercive field effectively decreased, while the dielectric constant increased. Loss tangent and fixed charge were found to be independent of the number of PZT/PT layers. These results are possibly explained by the enhanced crystallization resulting from the introduction of large number of nucleation sites in the multilayer film, and by the stacking of stable and dense PZT/PT layers. The thin film composed of three PZT/PT layers with a thickness of ∼450 nm exhibited dielectric constant of 1000, remnant polarization of 20 μC/cm2, coercive field of 40 kV/cm, and tan δ of 0.03. The relaxorlike ferroelectric behavior was observed with an increasing number of PZT/PT layers.