Electrical degradation in dielectric and piezoelectric oxides: Review of defect chemistry and characterization methods

The properties of dielectric and piezoelectric oxides are determined by their processing history, crystal structure, chemical composition, microstructure, dopants (or defect) distribution, and defect kinetics. Significant advances in understanding the materials, processing, properties, and reliability of these materials have led to their widespread use in aerospace, medical, military, transportation, power engineering, and communication applications, where they are used as ceramic discs, thick and thin films, multilayer devices, etc. Appropriate engineering of the defect chemistry and the correlated charge transport mechanisms is a pivotal element for the successful commercialization of perovskite oxides. Therefore, the exploration of optical, thermal, electrical, and structural techniques, and their application in investigating defects in perovskites, is critical. This review delves into electrical degradation in dielectrics and piezoelectrics, focusing on defect chemistry and key characterization techniques to assess the failure modes. In particular, it provides a detailed discussion of various spectroscopic, microscopic, and electronic characterization techniques essential for analyzing defects and degradation mechanisms.