Effect of Lanthanum Doping on Leakage Currents of Sol-Gel PZT Thin Films

Effect of La doping on polarization properties and leakage current of lead zirconate titanate (PZT) Pb(Zr0.48Ti0.52)O3 films is studied. In the low-voltage region (up to 80 – 90 kV/cm), the leakage current is determined by the resistance of depletion region of the reverse-bias Schottky barrier, and it is independent of La content. In the high-voltage region after the Schottky barrier breakdown, the leakage current depends on bulk resistance of PZT film along with the strong dependence on La content. The PZT film containing about 2% La has the values of polarization and coercive field (7 μC/cm2, 25 kV/cm) acceptable for FRAM applications along with minimum leakage currents.