Copper cofired dielectrics may give new opportunities for high temperature capacitors. To demonstrate feasibility, BaTiO3 has been formulated into X7R dielectrics with copper inner electrodes. This requires the development of a formulation that permits sintering at temperatures below 1000°C, and then firing in a reducing environment in atmospheres pO2 ∼ 10-8 atms. ZnO-B2O3 chemistries were explored with additional dopants to modify densification and the temperature coefficient of capacitance of the BaTiO3 dielectric anomaly. X7R characteristics with relative dielectric permittivities ∼2750 and tanδ ∼ 0.01 at 1 kHz were obtained at room temperature. Multilayer capacitors were fabricated in 3.2 mm × 1.6 mm size multilayers with an acrylic binder system and oxidation resistive copper inner electrodes.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Mechanics of Materials
- Electrical and Electronic Engineering
- Materials Chemistry