Grain boundary engineering of 2D materials for nano-ionic Resistive Switches
Synthesis and Properties of Functional Materials
Final Report Abstract
Conventional Complementary Metal-Oxide-Semiconductor (CMOS) technology and especially Flash based non-volatile memories are approaching serious technological challenges in the near future. Several alternative computing and memory devices are part of current research and concepts beyond traditional von Neumann computing emerged in prototypical devices. Among these devices are resistive switching memories which are nanoionic solid state random access memory devices offering scalability to an almost atomic level and extremely low power operation. Besides their advantages device degradation, endurance and stability issues and their yet not fully understood working principle are major obstacles for their application in novel microprocessors and memory devices on an industrial scale. The device degradation and stability problems mainly arise from uncontrolled diffusion, oxidation and reduction of ions involved in the switching process. Two dimensional (2D) materials have been recently suggested as ultra-thin barriers to improve the device performance parameters such as suppressing unintentional chemical diffusion. However, only little is understood about how these layers can be precisely tuned to allow sufficient supply of mobile ions while simultaneously still acting as diffusion barriers, and how these layers may be further integrated in a fabrication friendly way in practical devices. The main objective of this research project is to integrate and characterize 2D layers in resistive switching structures and to probe how the properties of these layers, in particular by making use of defects and grain boundary manipulation, can be tuned to improve the performance parameters of resistive switches. Within the scope of the project, fabrication processes for direct chemical vapour deposition or ultra-clean transfer-based deposition of graphene and hexagonal boron nitride (hBN) for integrated resistive switches have been established and characterized. The degradation problems in resistive switches have been further studied by electron microscopy and the project is the first to report about STEM tomography on resistively switching structures. The results of this project gain deeper insight in the working principle of resistive switching devices.
Publications
- "Catalyst Interface Engineering for Improved 2D Film Lift-Off and Transfer" ACS Applied Materials & Interfaces 8 33072–33082 (2016)
Wang, R., Whelan, P., Braeuninger-Weimer, P., Tappertzhofen, S., Alexander-Webber, J., Van-Veldhoven, Z., Kidambi, P., Jessen, B., Booth, T., Boggild, P., Hofmann, S.
(See online at https://doi.org/10.1021/acsami.6b11685)
