Fabrication of Ceramic Dielectrics on Base-Metal Foils for Embedded Capacitors

摘要

Development of power electronics system devices with higher performance, improved reliability, and smaller size and weight requires the passive components to be embedded within a printed wire board (PWB). The "film-on-foil" approach for depositing the passive component on base-metal foil is the most viable fabrication method for embedding the components within a PWB. We have deposited high-permittivity lead lanthanum zirconate titanate (PLZT) ceramic dielectric films on base metal foils by a chemical solution deposition technique. These prefabricated "film-on-foil" dielectric sheets can be embedded into PWBs for power electronics applications. We have measured a dielectric constant of 1300 (at 25°C) and 1800 (at 150°C), leakage current density of 6.6 × 10~(-9) A/cm~2 (at 25°C) and 1.4 × 10~(-8) A/cm~2 (at 150°C), and breakdown field strength of ≈2.5 MV/cm on PLZT films deposited on conductive lanthanum nickel oxide-buffered Ni foils. Also, initial results were encouraging with samples of PLZT on Cu foils processed under a controlled atmosphere, which gave dielectric constant >500. The dielectric properties of film-on-foil PLZT samples are presented in this paper.