Design of a bilayer ceramic capacitor with low temperature coefficient of capacitance

• Published in: Applied physics letters Vol. 109; no. 8
• Main Authors: Foeller, P. Y., Dean, J. S., Reaney, I. M., Sinclair, D. C.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 22-08-2016
• Subjects: Applied physics; Barium titanates; Capacitance; Capacitors; Dielectric loss; Electronics; Low temperature
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4961616

We show how a simple bilayer system that combines a layer of undoped BaTiO3 (BT) with a second layer of Ba0.975Na0.025Ti0.975Nb0.025O3 (2.5NNBT) can be used to improve the temperature coefficient of capacitance (TCC) of BaTiO3-based materials for capacitor applications. The bilayer system emulates the volume ratio between a conventional core and shell phase microstructure allowing a simple resource efficient approach to optimise the system for low TCC. Optimisation was achieved with a volume ratio of 0.67 2.5NNBT with 0.33 BT and results in a TCC of ±6% over the temperature range ∼25 to 125 °C whilst maintaining a permittivity of εr ∼ 3000 and low dielectric loss.