Chemical Solution Deposition of High-Quality SrRu O3 Thin-Film Electrodes and the Dielectric Properties of Integrated Lead Lanthanum Zirconate Titanate Films for Embedded Passives

Ferroelectric film-on-foil capacitors are suitable to replace discrete passive components in the quest to develop electronic devices that show superior performance and are smaller in size. The film-on-foil approach is the most viable method to fabricate such components. Films of Pb0.92La0.08Zr0.52Ti0.48O3 (PLZT) were deposited on SrRuO3 (SRO) buffer films over nickel and silicon substrates. High-quality polycrystalline SRO thinfilm electrodes were first deposited by chemical solution deposition. The optimized crystallization temperature of the SRO films was determined by studying the phase, microstructure, and electrical properties. A phase pure, dense, uniform microstructure with grain size < 100 nm was obtained in films crystallized between 700 and 750°C. The room-temperature resistivity of the SRO films crystallized at 700°C was ~800–900 μΩ-cm. The dielectric properties of sol-gel derived PLZT capacitors on SRO-buffered nickel were evaluated as a function of temperature, bias field, and frequency, and the results were compared to those of the same films on silicon substrates. The comparison demonstrated the integrity of the buffer layer and its compatibility with nickel substrates. Device-quality dielectric properties were measured on PLZT films deposited on SRObuffered nickel foils and found to be comparable to those for PLZT on SRO-buffered silicon and expensive platinized silicon. These results suggest that SRO films can act as an effective barrier layer on nickel substrates suitable for embedded capacitor applications.