TY - JOUR
T1 - The influence of Mn doping on the leakage current mechanisms and resistance degradation behavior in lead zirconate titanate films
AU - Akkopru-Akgun, Betul
AU - Bayer, Thorsten J.M.
AU - Tsuji, Kosuke
AU - Randall, Clive A.
AU - Lanagan, Michael T.
AU - Trolier-McKinstry, Susan
N1 - Funding Information:
The authors gratefully acknowledge financial support from the Center for Dielectrics and Piezoelectrics and the National Science Foundation under grant nos. IIP-1361571 and IIP-1841453 . The authors thank Minoru Ryu for TEM analysis.
Publisher Copyright:
© 2021 Acta Materialia Inc.
PY - 2021/4/15
Y1 - 2021/4/15
N2 - 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 Pb2+ and Pb3+. 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 Mn3+ to Mn2+ and Mn2+ to Mn3+ respectively.
AB - 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 Pb2+ and Pb3+. 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 Mn3+ to Mn2+ and Mn2+ to Mn3+ respectively.
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U2 - 10.1016/j.actamat.2021.116680
DO - 10.1016/j.actamat.2021.116680
M3 - Article
AN - SCOPUS:85101362600
VL - 208
JO - Acta Materialia
JF - Acta Materialia
SN - 1359-6454
M1 - 116680
ER -