Growth and study of antiferroelectric lead zirconate thin films by pulsed laser ablation

Abstract

Antiferroelectric lead zirconate (PZ) thin films were deposited by pulsed laser ablation on platinum-coated silicon substrates. Films showed a polycrystalline pervoskite structure upon annealing at 650 °C for 5–10 min. Dielectric properties were investigated as a function of temperature and frequency. The dielectric constant of PZ films was 220 at 100 kHz with a dissipation factor of 0.03. The electric field induced transformation from the antiferroelectric phase to the ferroelectric phase was observed through the polarization change, using a Sawyer–Tower circuit. The maximum polarization value obtained was 40 μC/cm2. The average fields to excite the ferroelectric state, and to reverse to the antiferroelectric state were 71 and 140 kV/cm, respectively. The field induced switching was also observed through double maxima in capacitance–voltage characteristics. Leakage current was studied in terms of current versus time and current versus voltage measurements. A leakage current density of 5×10−7 A/cm2 at 3 V, for a film of 0.7 μm thickness, was noted at room temperature. The trap mechanism was investigated in detail in lead zirconate thin films based upon a space charge limited conduction mechanism. The films showed a backward switching time of less than 90 ns at room temperature.