Transmission Electron Microscopy Study on the Effect of Thermal and Electrical Stimuli on Ge2Te3 Based Memristor Devices

Frontiers in Electronics

Austin Shallcross¹  Guru Subramanyam¹  Eunsung Shin¹  Sabyasachi Ganguli²  Ajit Roy²  Rohan Dhall³  Md Shahanur Alam⁴  Tarek Taha⁴  Cynthia Bowers⁵  Benson Athey⁵  Krishnamurthy Mahalingam⁵  Albert Hilton⁵ 

[1] Center of Excellence for Thin-film Research and Surface Engineering (CETRASE), Department of Electrical and Computer Engineering, University of Dayton, Dayton, OH, United States;Materials and Manufacturing Directorate, Air Force Research Laboratory, Dayton, OH, United States;National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, United States;Parallel Cognitive Systems Lab, Department of Electrical and Computer Engineering, University of Dayton, Dayton, OH, United States;Universal Energy Systems, Dayton, OH, United States;

关键词: memristor;    chalcogenide;    phase change materials;    resistive switching;    resistive memory;    TEM;   

DOI  :  10.3389/felec.2022.872163

来源: DOAJ

【 摘 要 】

Memristor devices fabricated using the chalcogenide Ge2Te3 phase change thin films in a metal-insulator-metal structure are characterized using thermal and electrical stimuli in this study. Once the thermal and electrical stimuli are applied, cross-sectional transmission electron microscopy (TEM) and X-ray energy-dispersive spectroscopy (XEDS) analyses are performed to determine structural and compositional changes in the devices. Electrical measurements on these devices showed a need for increasing compliance current between cycles to initiate switching from low resistance state (LRS) to high resistance state (HRS). The measured resistance in HRS also exhibited a steady decrease with increase in the compliance current. High resolution TEM studies on devices in HRS showed the presence of residual crystalline phase at the top-electrode/dielectric interface, which may explain the observed dependence on compliance current. XEDS study revealed diffusion related processes at dielectric-electrode interface characterized, by the separation of Ge2Te3 into Ge- and Te- enriched interfacial layers. This was also accompanied by spikes in O level at these regions. Furthermore, in-situ heating experiments on as-grown thin films revealed a deleterious effect of Ti adhesive layer, wherein the in-diffusion of Ti leads to further degradation of the dielectric layer. This experimental physics-based study shows that the large HRS/LRS ratio below the current compliance limit of 1 mA and the ability to control the HRS and LRS by varying the compliance current are attractive for memristor and neuromorphic computing applications.

【 授权许可】

Unknown