Effect of PbO content on the properties of sol-gel derived PZT films

The PbO content of lead zirconate titanate(PZT) films has been widely recognized as affecting not only the phase assembly and microstructure but also the dielectric and ferroelectric properties. Excess PbO has often been incorporated in PbO-based films to optimize the film properties by compensating for PbO loss either through volatilization or diffusion into the substrates. Sol-gel derived PZT 53/47 films with various PbO contents, i.e., Pb_x Zr_0.53 Ti_0.47O₃ (x = 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.05, 1.10, 1.25 and 1.5) were prepared on platinized Si wafers and fired to temperatures ranging from 550C to 700C under oxygen. Multiple spincoating with an intermediate firing of 400C between coatings was performed to obtain films up to 0.5 urn thick. After the final crystallization firing, top Pt electrodes were sputtered to form monolithic capacitors. These capacitors were subjected to dielectric and ferroelectric characterization using an impedance analyzer and a Radiant Technologies RT66A Ferroelectric Test System. XRD was used to study the phase development and phase assembly of the fired films. The dielectric and ferroelectric properties of the films are discussed with respect to the effects of PbO content on the phase assembly, microstructure and processing conditions.