Evolution of Internal Stress and Influence on Dielectric Properties by Number of Dielectric Layers in MLCC
We researched the phenomenon that the permittivity of dielectric layers in multilayer ceramic capacitor (MLCC) increases with the number of dielectric layers. Finite element method (FEM) shows that the internal residual stress in MLCC was generated by the difference of thermal expansion coefficient between internal electrodes and dielectric layers. We developed a electric measurement system with applying external stress for understanding the stress influence on dielectric properties. The compressive stress along electric field increased the polarization. The polar nano regions (PNRs) in shell composition dielectrics were easily influenced by stress. Based on these results, the relationship between the number of dielectric layers and their permittivity in MLCCs was explained.
Shinobu Fujihara and Tadashi Takenaka
S. Yokomizo et al., "Evolution of Internal Stress and Influence on Dielectric Properties by Number of Dielectric Layers in MLCC", Key Engineering Materials, Vol. 445, pp. 31-34, 2010