Pure and modified lead titanate thin films by sol-gel

Pure and modified lead titanate thin films were fabricated by spin coating an alkoxide-based solution onto platinum-coated silicon substrates. The solution was made by combining lead acetate trihydrate, titanium IV isopropoxide, and diethanolamine in isopropanol with lanthanum as a dopant. Various heating schedules and techniques were examined to optimize the dielectric and microstructural properties of the films. The films were tested for dielectric and hysteresis properties, and characterized by various methods. Perovskite PbTiO₃ was found to form at approximately 400°C and could be obtained by heating for short soaking durations of 10 min per layer. Measured at 1 kHz, an average dielectric constant of 410 was obtained for pure lead titanate films heated at 500°C for 1 h. Hysteresis measurements taken on these films at 100 Hz revealed an average remanent polarization of 11 μC/cm² with a coercive field of approximately 75 kV/cm. The films doped with 5% lanthanum exhibited a dielectric constant of 825 with a coercive field of 52 kV/cm and a remanent polarization of 25 μC/cm²