Lead zirconate titanate (PZT) film capacitor with a multilayer construction

Thin PZT film is being developed for use in microelectronics, electromechanical and optoelectronic applications. Thin Pb(ZrTi)O₃ film capacitor devices were fabricated using RF sputtering techniques. The multiple-layer configuration of Si/SiO₂/Ti/Pd or Pt was used as the substrate and bottom electrode. The top electrode was either Pd or Pt. At room temperature, the typical dissipation factor of this PZT film capacitor was 0.083 at 1 kHz. These PZT film capacitors had a parallel resistance of 1.15 mega-ohm. The film capacitor has an energy storage density of 0.023 μF/cm². With the thickness of the film being 12,000 Å, the dielectric constant was calculated to be 32. The insulation resistance was 138 giga-ohm. The resistivity was calculated to be 8.1×10¹⁰ ohm-cm. These film capacitors were tested at 50 volts and the corresponding leakage current was at 1×x10^-5 amp/cm². The breakdown strength at this stage was 4.2×10⁵ V/cm. Annealing at 400°C increased the value of the dielectric constant about 38%. The dissipation factor was decreased to 0.023 at 1 kHz. The parallel resistance increased from 1.15 to 3.01 mega-ohm. The insulation resistance after annealing was increased to 2180 giga-ohm. The resistivity was increased to 1.28×10¹³ ohm-cm. The energy storage density of this film capacitor was increased from 0.023 to 0.031 μF/cm². These film capacitors produced to-date had little dependence on frequency from 400 Hz to 100 kHz. The PZT sample with a thickness of 4.2 μm exhibited a dielectric constant of 107 before annealing and 354 after annealed at 600°C. The dissipation factor was reduced from 0.12 to 0.015 before and after annealing at 600°C