Spontaneous recovery of hydrogen-degraded TiO₂ ceramic capacitors

Abstract

Degradation of TiO₂-based ceramic capacitors was observed after hydrogen incorporation on the termination electrodes of the capacitors via electrolysis of water. Fourier-transform infrared (FTIR) absorption spectra analysis of polished rutile single crystals clearly showed that hydrogen was incorporated into the TiO₂ lattice through the treatment. Hydrogen reduces Ti[sup 4+] to Ti[sup 3+] and increases the concentration of charge carriers. The degradation was found to exhibit a strong dependence on time at room temperature. The degraded properties were spontaneously recovered through an aging process, showing a spontaneous recovery unique to TiO₂-based ceramic capacitors. It is proposed that hydrogen is metastable in TiO₂ and that hydrogen-induced degradation has different stabilities among various oxide-based components and devices.