An Investigation Of The Doping On The PZT Thin Films

Recently, there has been an increased interest in ferroelectric lead zirconate titanate (Pb (ZrxTi_1-x)O₃, PZT)thin films for electric devices. PZT thin films have been widely used for a variety of applications such as ferroelectric memories, piezoelectric microsensors and actuators, pyroelectric detectors. So it is important to study the preparations, microstructure and properties of PZT ferroelectric thin films. This paper aimed systematically at studying the sol-gel techniques and properties of PZT ferroelectric thin films on the basis of the analysis of the progresses of ferroelectric materials. PZT ferroelectric films with crack-free and compact have been successfully fabricated. The influences of annealing temperature on the crystallinity formation of the PZT films prepared on ITO/glass substrates by sol-gel method have been investigated. The electric properties, ferroelectric hysteresis loops and leakage current density of the prepared thin films are also investigated. The result shows that the PZT films annealed at 600℃have good ferroelectric properties, electric properties and I-V properties. The Pr values of the films is 36.5μC/cm2, and the EC values of the films is 45.2KV/cm. This paper studied the properties of the PZT films modified by the introduction of some dopants. We have fabricated the PbCoy(Zr_xTi_1-x)O₃ films (PCZT films) with different proportions of Co-doped (a) 5mol%, (b) 10mol%, (c) 15mol%, and investigated the XRD, ferroelectric properties, electric properties and I-V properties. The result shows the Co dopant can prevent the formation of the pyrochlore phase in the process of annealing. The PCZT films have higher Pr values, higher EC values, larger dielectric constant (at 1K Hz) and larger leakage current density than PZT films. And we have summarized that 10mol% proportion of Co-doped is appropriate for PZT films. This paper also studied the properties of the PbCoyNbz(ZrxTi_1-x)O₃ films with Nb-doped (PCNZT films). We doped different proportions of Nb in the PCZT films with 10mol% Co-doped. The result shows that the Nb dopant can compensate the large leakage current density of the PCZT films. In the range of 1mol% and 10mol% doping proportions, the leakage current density decreased with the increasing proportions of Nb dopants, but the Pr values and dielectric constant also decreased.