Capacitance Enhancement of Doped Barium Titanate Dielectrics and Multilayer Ceramic Capacitors by a Post-Sintering Thermo-Mechanical Treatment

Abstract

High capacitance of miniaturized multilayer ceramic capacitors (MLCCs) is of great interest from both academic and industrial points of view. Because of the limited number of suitable materials (possessing high permittivity and low losses), the capacitance of MLCCs may be enhanced by modifying the capacitor geometry (i.e., by reducing the layer thicknesses or increasing the internal electrodes? area) and by optimizing the thermal schedule during processing. In this study, we describe a post-sintering thermo-mechanical treatment to increase the capacitance of dielectrics and MLCCs. A uniaxial mechanical load was applied during the cooling from either below or above the Curie temperature to room temperature. After load release, the permittivity permanently increased at room temperature by similar to 8%-11% after a stress of 20 MPa had been applied. The configuration of the ferroelectric domains and the residual stress may be responsible for this improvement.