Deposition of lead-zirconium-titanate (PZT) ferroelectric material over iridium metal, in the formation of a ferroelectric capacitor in an integrated circuit. The capacitor is formed by the deposition of a lower conductive plate layer having iridium metal as a top layer. The surface of the iridium metal is thermally oxidized, prior to or during the deposition of the PZT material. The resulting iridium oxide at the surface of the iridium metal is very thin, on the order of a few nanometers, which allows the deposited PZT to nucleate according to the crystalline structure of the iridium metal rather than that of iridium oxide. The iridium oxide is also of intermediate stoichiometry (IrO2-x), and reacts with the PZT material being deposited.