Phase and texture evolution in solution deposited lead zirconate titanate thin films: Formation and role of the Pt₃Pb intermetallic phase

Solution deposition is widely used for the fabrication of lead zirconate titanate (PZT) thin films on platinized silicon substrates. However, phase and texture evolution during the crystallization process is not well understood, particularly due to the difficulty in tracking changes in the thin films in situ during heating. In this work, we characterized phase and texture evolution in situ during heating and crystallization of PZT thin films using high-energy X-ray diffraction. Films were pyrolyzed at either 300 °C or 400 °C and heated at various rates between 0.5 °C/s and ∼150 °C/s. For films that were pyrolyzed at 300 °C, the most rapid heating rates first induced strong intensities from a transient Pt₃Pb phase. The Pt₃Pb phase inherited the texture of the pre-existing platinum layer. Combined with other observations, the results suggest the conversion of the platinum to the intermetallic phase near the interface due to the interdiffusion of lead. In all experimental variations, the pyrochlore phase was observed to form concurrently with the disappearance of the Pt₃Pb phase after which the perovskite phase ultimately crystallized. For films that were pyrolyzed at 400 °C, the Pt₃Pb phase was not observed at any of the heating rates; instead, the pyrochlore phase was first observed, followed by the perovskite phase. Independent of the pyrolysis temperature or observation of Pt₃Pb, a 111-dominant crystallographic texture formed in the perovskite phase when crystallized using fast heating rates. These results demonstrate that 111 textures in solution-derived PZT thin films are not correlated with the observation of Pt₃Pb or other intermetallic or transient phases.