Journal of the American Ceramic Society, Vol.91, No.3, 887-892, 2008
Evaluation of residual stress in a multilayer ceramic capacitor and its effect on dielectric behaviors under applied dc bias field
The residual stress in a multilayer ceramic capacitor (MLCC) has been evaluated by two-dimensional finite element simulation in combination with X-ray diffraction measurement. It is shown that there is a compressive in-plane stress in the active layers of the MLCC, which increases with increases in the number of dielectric layers when both dielectric layer thickness and electrode thickness are kept constant. A good order of magnitude agreement between the residual stresses obtained from two approaches is found. The epsilon-V response of the MLCC with different number of dielectric layers demonstrates that under a given or no applied field, the dielectric permittivity increases with increasing compressive stress. Additionally, under dc bias field, the higher the compressive in-plane stress existing in the MLCC, the more significant the decrease of the dielectric permittivity. These results can be explained through a phenomenological thermodynamic model, including both elastic and electrostatic energy, based on the Ginsburg-Landau-Devonshire theory.