Speaker: Dr. Betul Akkopru Akgun, Penn State University

Speaker:  Dr. Betul Akkopru Akgun, The Pennsylvania State University

Title:  The Role of Defect Chemistry in DC Resistance Degradation of Lead Zirconate Titanate Thin Films

Abstract

The trend towards further miniaturization of MEMS devices has dramatically increased the magnitude of the electric field distributed across the PZT film under an applied bias. As a result, the electrical reliability issues, among which the DC resistance degradation is the main limiting factor to PZT films’ lifetime, become of great concern. Therefore, it is crucial to reveal the nature and concentration of defects as well as associated charge transport mechanisms leading to electrical degradation in PZT films in order to control electrical breakdown and device failure. In this talk, I will describe the role of defects that can contribute to electronic and ionic conduction in PZT films. First, I will focus on the influence of variation in nature and distribution of point defects in PZT films due to (1) dopant type and concentration, (2) PbO non-stoichiometry, (3) Ti/Zr segregation, and (4) presence of redox active ions on DC resistance degradation and lifetime. Second, I will show how the interfacial defect chemistry can be controlled in PZT films through graded doping to improve the electrical reliability of PZT films. 

Biography

Dr. Betul Akkopru-Akgun is a postdoctoral fellow at Penn State University. She received her Ph.D. and a master’s degree in the Department of Materials Science and Engineering from Penn State University. She also holds a second M.Sc. degree in the Department of Metallurgical and Materials Engineering from the Middle East Technical University. Her research focuses on understanding the fundamentals that control the magnitude of the dielectric and piezoelectric responses and the reliability of the piezoelectric microelectromechanical systems (piezoMEMS). She has been invited to speak at the IEEE International Symposium on Applications of Ferroelectrics (ISAF) for her contribution to understanding the defect chemistry controlling electrical degradation in PiezoMEMS devices. She is the recipient of the Roy Robert E. Newnham Award for Research Excellence and the Rustum and Della Roy Innovation in Materials Research Award. She was recently nominated for the 2021 UFFC Ferroelectrics Young Investigator Award. She serves as a reviewer in several venues, including JACerS, JAP, APL, AFM, T-UFFC, IEEE ISAF-ISIF-PFM Joint Conference, and AIP Advances.