Effect of bottom electrodes on structures and electric properties of PLT ferroelectric thin films

Lead lanthanum titanate (PLT) thin films with 10% La and 5% excess Pb have been deposited on the Pt/Ti electrodes with different thickness of Ti layer by metal-organic compound decomposition process. XRD and SEM have been applied to investigate the microstructure and morphologies of the electrode and PLT thin films. The results show that the grain sizes of PLT thin films decrease from 150nm to 90nm with the increase of thickness of Ti layer. The thickness of PLT films has a dominant effect on dielectric and ferroelectric properties of PLT films. The dielectric constants of thin films annealed at 550°C for 1h increase from 500 to 580 with the increase of thickness of Ti layer and the dielectric loss tangent is not more than 2%. The remnant polarization is between 6.32-7.63 μC/cm² and the coercive field is about 68.9 kV/cm-83.7 kV/cm at 1 kHz. The leakage current without Ti layer is larger than that with Ti layer. The leakage current is associated with the defects in thin films.