We report on the microstructural analyses, by means of X-ray diffraction (XRD), scanning electron microscopy combined with energy dispersive X-ray analysis (SEM-EDX) and cross-section transmission electron microscopy (X-TEM), of chemically prepared Pb(Zr0.3Ti0.7)O-3 thin films deposited on IrO2 substrates. The purpose of this study is to detail temperature and time dependence of the lead zirconate titanate (PZT) film microstructure on this type of conductive oxide substrate, partly through a comparison with identically processed PZT films deposited on Pt substrates. It was observed that PZT 30/70 films on IrO2 bottom electrodes, fired at temperatures up to 620 degreesC, are not single phase, due to extensive lead losses during the processing. The IrO2 substrate was found to be indirectly responsible for these losses. Nevertheless, good ferroelectric properties were measured (P-r was 50 muC/cm(2) for the 620 degreesC film). Based on the observed morphology and texture with increasing annealing time, a mechanism for phase evolution in sol-gel-derived PZT 30/70 films on IrO2 substrates is proposed. (C) 2004 Elsevier B.V. All rights reserved.