High-energy density dielectrics and capacitors for elevated temperatures: Ca (Zr, Ti) O₃

The Ca(Zr_1-xTi_x)O₃ (CZT) solid solution system is a linear dielectric that is of interest for high-temperature power capacitor applications. This dielectric was synthesized by conventional solid-state processes and prototyped into single-layer CZT capacitors, which were fabricated with interdigitated electrodes cofired between dielectric layers ∼10-μm thick. The dielectric properties of these capacitors were extensively investigated as a function of Zr/Ti ratio on the CaZrO₃ side of the solid solution. The electrostatic energy density and breakdown strength of the CZT capacitors were investigated by measuring polarization-electric field curves as a function of temperature from room temperature to 250°C. The Ca(Zr_0.80Ti_0.20)O ₃ capacitors show high electrostatic energy density of 4 J/cm ³ at 250°C. Highly accelerated life testing (HALT) was also performed on these dielectrics, and we quantified the thermal stimulated depolarization current (TSDC) to access the major point defects in the CZT system.