Characterization of Pb(Zr,Ti)O3 thin films deposited from multielement metal targets

Abstract

Lead zirconate titanate [Pb(Zr,Ti)O3 or PZT] thin films have been grown by sputtering a multi-element metal target in oxygen using dc planar magnetron sputtering. Growth parameters and annealing conditions have been optimized. The kinetics of reactive sputtering and the implications of sputtering parameters on film composition have been studied. The studies reveal the requirement for operation at low substrate temperatures (200 °C), high sputtering pressures (4–5 Pa), and a large substrate-to-target distance (10 cm) for obtaining good control over composition. The structural and electrical properties of films were found to depend on the compositional ratio of Zr/Ti, similar to that observed in bulk PZT ceramics. Films having a resistivity of 1010 Ω cm and a dielectric constant ε′∼820 at room temperature (300 K) have been achieved. Ferroelectric hysteresis loop measurements indicated a remanent polarization of 30.0 μC/cm2 and coercive field of 25 kV/cm for the rhombohedral phase composition (Zr/Ti=58/42). Piezoelectric activity in the films is reported for the first time, through the fabrication of a surface-acoustic-wave delay line on a poled polycrystalline PZT thin film.