Processing and characterization of Pb(Zr,Ti)O-3 films, up to 10 mu m thick, produced from a diol sol-gel route

A recently developed diol sol-gel route has been modified in order to produce multilayer PbZr0.53Ti0.47O3 films on platinized sapphire substrates. Up to 20 depositions of a 1.1 M sol were carried out leading to a final film thickness of 10 mu m. A similar thickness could be achieved from 12 coatings of a more concentrated 1.6 M sol, Decomposition and crystallization of the multilayer coatings were performed using a two-stage prefiring sequence, at 350 degrees C and 600 degrees C, followed by a final firing step at 700 degrees C. Ferroelectric remanant polarization increased with increasing film thickness to a value of 40 mu C cm(-2) for a 10 mu m film, with a corresponding coercive field of 30 kV cm(-1); the relative permittivity of this film was similar to 1000 and the dissipation factor 0.04. The thickness dependence of relative permittivity could be modeled on a simple series capacitor circuit representing the ferroelectric Pb(Zr, Ti)O-3 (PZT) film and low-permittivity interface layers; but other possible contributory factors are also discussed.