Ceramic processing strategies for thick films on copper foils

Functional oxides on Cu have multiple applications. For thick films the required high sintering temperatures present a challenge for processing on base metal substrates. In this study it is shown that it is possible to adapt well-known ceramic processing strategies to the fabrication of thick lead zirconate titanate (PZT) films on Cu with useful ferroelectric properties. PZT powders with optimized particle sizes are used to fabricate thick films by electrophoretic deposition in combination with a post-deposition isostatic pressing step. This approach to maximize green packing is sufficient to dramatically lower the required sintering temperatures. 25 μm thick PZT films on Cu sintered at 900 °C have a dielectric permittivity of 585, a loss tangent at 10 kHz of 0.03, a remanent polarization of 19 μC cm−2 and a coercive field of 22 kV cm−1. This significant improvement in the dielectric response opens the possibility of using thick PZT films on Cu for a wide range of devices where cost, yield and reliability are concerns.