Development of PLZT film-on-foil capacitors with high energy density

Ceramic thin films with high dielectric constant and high breakdown strength hold special promise for advanced electronics applications. We deposited lanthanum-doped lead zirconate titanate (PLZT) on base metal foils (film-on-foils) by chemical solution deposition. The PLZT film-on-foils were characterized over a wide temperature range between room temperature and 200°C. For ≈2-μm-thick PLZT films grown on LaNO₃-buffered nickel foils at room temperature, we measured a dielectric constant of ≈1300, dielectric loss of ≈0.07, remanent polarization of ≈26 μC/cm ², coercive field of ≈29 kV/cm, leakage current density of ≈9.2 × 10^-9 A/cm², and energy density of ≈67 J/cm³. Dielectric breakdown strength was determined to be ≈2.6 × 10⁶ V/cm by Weibull analysis. These and other results reported here indicate that electronic devices with film-on-foil capacitors would possess higher performance, improved reliability, and enhanced volumetric and gravimetric efficiencies compared with traditional dielectric capacitors.