Dielectric Characterization of Bulk and Pt/ZrO₂/BaTiO₃/ZrO₂/Pt Thin Film Capacitors: Thickness Scaling and Interface Engineering for Energy Storage

Ba(Zr_0.2Ti_0.8)O₃ (BZT) based capacitors are promising candidates for dielectric energy storage; however, the transition from bulk ceramics to nanoscale thin film devices is often limited by increased leakage current and reduced reliability. In this work, a systematic investigation is carried out to bridge bulk ceramic behavior and thin-film capacitor design through a combined experimental and simulation-based approach. Ag/BZT/Ag bulk ceramic capacitors were fabricated using the conventional solid-state reaction method and experimentally characterized. Thickness scaling effects were then analyzed by simulating an Ag/BZT/Ag capacitor with the dielectric thickness reduced to 104 nm while preserving the same lateral dimensions. Furthermore, a Pt/ZrO₂/BaTiO₃/ZrO₂/Pt thin-film capacitor architecture incorporating ZrO₂ interfacial barrier layers was modeled to suppress leakage current. The results demonstrate that thickness scaling significantly enhances capacitance and energy density but leads to a pronounced increase in leakage current density due to intensified electric fields and charge injection. The introduction of ZrO₂ barrier layers and high-Schottky-barrier Pt electrodes effectively suppresses leakage current and dielectric loss, at the cost of reduced capacitance density due to series capacitance effects. This study provides a comprehensive framework linking bulk ceramic performance, thickness scaling limitations, and interface-engineered thin-film design, offering valuable guidelines for the development of high-performance dielectric energy storage capacitors.