Stored charge in tantalum capacitors - Latent and manifest mavericks

Space-charge fields can be established in Ta-Ta2O5-MnO2 capacitor structures either by the mechanism of ionizing radiation with forward bias (tantalum electrode positive), or by the mechanisms of reverse bias without irradiation, or forward bias without irradiation. In all the tantalum capacitors, charge is stored by the first two mechanisms; only when a persistent space-charge polarization field can be established by the third mechanism (forward bias without irradiation) is the unit called a maverick. Maverick radiation response in capacitors is caused by charge injection and storage within the oxide. It is noted that the only way to produce maverick capacitors with a high frequency of occurrence in the laboratory is through application of reverse bias. Therefore, the application of reverse bias to a simple capacitor intended for low-bias applications or to back-to-back pairs should be avoided both in the manufacture and checkout of circuits.