Atomic-Scale Imaging of Polarization Switching in an (Anti-)Ferroelectric Memory Material: Zirconia (ZrO2)
Sarah Lombardo, Christopher T. Nelson, Kisung Chae, Sebastian E. Reyes‐Lillo, Mengkun Tian, Nujhat Tasneem, Z. Wang, Michael Hoffmann, Dina H. Triyoso, Steven Consiglio, Kandabara Tapily, Robert D. Clark, G. J. Leusink, Kyeongjae Cho, Andrew C. Kummel, Josh Kacher, Asif Islam Khan
Abstract
Direct, atomic-scale visualization of polarization switching in a functional, polycrystalline, binary oxide via in-situ high-resolution transmission electron microscopy (HRTEM) biasing is reported for the first time. Antiferroelectric (AFE) ZrO2 was used as the model system, which is important for commercial DRAMs and as emerging NVMs (through work-function engineering). We observed (1) clear shifting and coalescing of domains within a single grain, and (2) dramatic changes of the atomic arrangements and crystalline phases—both at voltages above the critical voltage measured for AFE switching. Similar synergistic in-situ structural-electrical characterization can pave the way to understand and engineer microscopic mechanisms for retention, fatigue, variability, sub-coercive switching and analog states in ferroelectric and AFE-based memory devices.