R&D: Stopping Voltage-Dependent PCM and RRAM-Based Neuromorphic Characteristics of Germanium Telluride

Advanced Functional Materials has published an article written by Yawar Abbas, Department of Physics, Khalifa University, Abu Dhabi, 127788 United Arab Emirates, and System on Chip Lab, Khalifa University, Abu Dhabi, 127788 United Arab Emirates, Sumayya M. Ansari, Department of Physics, United Arab Emirates University, Al Ain, 15551 United Arab Emirates, Inas Taha, Department of Physics, United Arab Emirates University, Al Ain, 15551 United Arab Emirates, Heba Abunahla, System on Chip Lab, Khalifa University, Abu Dhabi, 127788 United Arab Emirates, Department of Electrical Engineering and Computer Science, Khalifa University, Abu Dhabi, 127788 United Arab Emirates, and Quantum and Computer Engineering Department, Delft University of Technology, Delft, 5058 Netherlands, Muhammad Umair Khan,System on Chip Lab, Khalifa University, Abu Dhabi, 127788 United Arab Emirates, and Department of Electrical Engineering and Computer Science, Khalifa University, Abu Dhabi, 127788 United Arab Emirates, Moh’d Rezeq, Department of Physics, Khalifa University, Abu Dhabi, 127788 United Arab Emirates, and System on Chip Lab, Khalifa University, Abu Dhabi, 127788 United Arab Emirates, Haila M. Aldosari, Department of Physics, United Arab Emirates University, Al Ain, 15551 United Arab Emirates, and Baker Mohammad, System on Chip Lab, Khalifa University, Abu Dhabi, 127788 United Arab Emirates, and Department of Electrical Engineering and Computer Science, Khalifa University, Abu Dhabi, 127788 United Arab Emirates.

Abstract: “Recently, phase change chalcogenides, such as monochalcogenides, are reported as switching materials for conduction-bridge-based memristors. However, the switching mechanism focused on the formation and rupture of an Ag filament during the SET and RESET, neglecting the contributions of the phase change phenomenon and the distribution and re-distribution of germanium vacancies defects. The different thicknesses of germanium telluride (GeTe)-based Ag/GeTe/Pt devices are investigated and the effectiveness of phase loops and defect loops future application in neuromorphic computing are explored. GeTe-based devices with thicknesses of 70, 100, and 200 nm, are fabricated and their electrical characteristics are investigated. Highly reproducible phase change and defect-based characteristics for a 100 nm-thick GeTe device are obtained. However, 70 and 200nm-thick devices are unfavorable for the reliable memory characteristics. Upon further analysis of the Ag/GeTe/Pt device with 100 nm of GeTe, it is discovered that a state-of-the-art dependency of phase loops and defect loops exists on the starting and stopping voltage sweeps applied on the top Ag electrode. These findings allow for a deeper understanding of the switching mechanism of monochalcogenide-based conduction-bridge memristors.“