What happens during dielectric breakdown in a ceramic capacitor?

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Figure 1: Ferroelectric properties of barium titanate (BaTiO3). (Left) Above 120° C the structure of the BaTiO3 crystal is cubic, and there is no net polarization of charge; (right) below 120° C the structure changes to tetragonal, shifting the relative positions of the ions and causing a concentration of positive and negative charges toward opposite ends of the crystal. — capacitor dielectric and piezoelectric ceramics Figure 1: Ferroelectric properties of barium titanate (BaTiO₃). (Left) Above 120° C the structure of the BaTiO₃ crystal is cubic, and there is no net polarization of charge; (right) below 120° C the structure changes to tetragonal, shifting the relative positions of the ions and causing a concentration of positive and negative charges toward opposite ends of the crystal.

During dielectric breakdown in a ceramic capacitor, the material experiences a sudden failure that results in a catastrophic discharge through the dielectric. This process typically causes irreversible damage to the ceramic component. In the specific case of barrier-layer (BL) capacitors, which are designed with extremely thin resistive layers to achieve high dielectric constants, the local electric fields can become so intense that they trigger this breakdown.1