Dielectric Breakdown in Solid Electrolyte Tantalum Capacitors

The construction of solid electrolyte tantalum capacitors is described briefly. The evidence for flaws in the oxide dielectric is presented and the leakage current flowing during the early stages of breakdown is discussed. A consideration of the variation of breakdown voltage with temperature and time of apolication of voltage leads to the conclusion that thermal breakdown is responsible for failure in the dielectric. A description is given of selfhealing and its significance is considered.