The influence of Mn doping on the leakage current mechanisms and resistance degradation behavior in lead zirconate titanate films. (15th April 2021)

• Record Type: Journal Article
• Authors: Akkopru-Akgun, Betul; Bayer, Thorsten J.M.; Tsuji, Kosuke; Randall, Clive A.; Lanagan, Michael T.; Trolier-McKinstry, Susan
• Is Part Of: Acta materialia. Volume 208(2021)
• Publication Date: 2021-04-15
• Subjects: Electrical degradation -- PZT, Thin films -- Defect chemistry -- Electrical conduction; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2021.116680
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: The electrical reliability of lead zirconate titanate (PZT) films was improved by incorporating Mn; the time dependent dielectric breakdown lifetimes and the associated activation energy both remarkably increased with Mn concentration. The correlation between the defect chemistry and the resistance degradation was studied to understand the physical mechanism(s) responsible for enhanced electrical reliability. At lower electric fields, Poole-Frenkel emission was responsible for the leakage current. Beyond a threshold electric field, Schottky emission controlled the leakage. After electrical degradation of a 2 mol.% Mn doped PZT film, no significant change in potential barrier height for injecting electrons from the cathode into the anode was observed. This suggests that the degradation is mostly controlled by Poole-Frenkel conduction via some combination of hole migration between lead vacancies, small polaron hopping between Mn sites, and hole hopping between Pb 2+ and Pb 3+ . No variation in the valence state of Ti near the cathode was observed in degraded Mn doped PZT films, implying that multivalent Mn provides trap sites for electrons and holes; free electron generation due to compensation of oxygen vacancies at the cathode and free hole formation at the anode region might be suppressed by the valence changes from Mn 3+ to Mn 2+ and Mn 2+ to Mn 3+ respectively. Graphical abstract: Image, graphical abstract