The effects of hydrolysis on the degree of polymerization during metallo-organic solution deposition of lead zirconate titanate (PZT) films have been investigated. The reaction of lead 2-ethylhexanoate, zirconium n-tetrapropoxide, and titanium tetrabutoxide in isopropanol with water were studied using thermogravimetry, specular reflectance Fourier transform infrared spectroscopy (FTIR) and optical and electron microscopy.
Films prepared from coating solutions having varying amounts of water exhibited dramatic differences in morphology. The films were spin-coated on platinum coated fused silica substrates and annealed at 525°C for 30 minutes. Unhydrolyzed coating solutions and solutions with a mole ratio of water to total metal of 0.5 yielded perovskite films with 0.5–5μm grains. A mole ratio of 1.5 (the amount of water required to completely hydrolyze the metallo–organics in the solution) formed amorphous, porous films. The stability of the prepolymerized films inhibits crystallization and densification at moderate temperatures.