Oxide Thin Film Heterostructures on Large Area, with Flexible Doping, Low Dislocation Density, and Abrupt Interfaces: Grown by Pulsed Laser Deposition

Figure 19

Temperature dependence of capacity C=𝜖₀𝜖_r A/d (A is electrode area and d thickness of dielectric) of thin film capacitors, measured with 50 mV AC amplitude at 1 kHz and zero DC-bias. The dielectric was Ba_0.6Sr_0.4TiO₃ (BSTO-0.6, black line), BSTO-0.8 (green), and BTO (red). With decreasing Ba substitution, the ferroelectric Curie temperature (maximum of 𝜖_r) increases. This structural phase transition is remarkably broadened due to the thin film nature of the dielectric. For C=100 nF, d=1 μm, and 3 mm circular electrodes, the relative permittivity 𝜖_r of the dielectric is above 1,600.