BaTiO3–P(VDF-TrFE) composite ink properties for printed decoupling capacitors

In this research a composite for printable capacitors using screen printed structures and low temperature curing ferroelectric ink was investigated. The realized ink consisted of 40 vol% barium titanate in a poly(vinylidenefluoride-trifluoroethylene) matrix. DuPont silver ink 5064H was used for the conductive lines in the design and the maximum process temperature was 130 °C. The thickness of the composite and the area of the printed capacitor were 43 μm and area 25 mm2, respectively. The obtained relative permittivity of the composite was 46 and the tan δ was 0.15 at 1 MHz. Additionally, the microstructure of the composite was investigated and the temperature dependence of the dielectric properties measured. The capacitance of the parallel plate structure was approximately 200 pF at 1 MHz. This is easily adjustable by changing the printing pattern, number of layers or the filler loading. The freedom of choice in integration and capacitance value selection makes the ink highly usable in, for example, decoupling capacitors that are compatible with inorganic, organic and even flexible, substrates.