Data-centric technologies are rapidly growing with new applications emerging, raising the need for electronic devices with lower power consumption, durable embedded memories (volatile and non-volatile), and operating at high computational speed. One of the most promising solutions to this is neuromorphic computing, which emulates the working principles that the human brain uses for information processing, and it holds the key to flexible computation and efficient machine learning applications.
The vision of EROS is to nanoengineer and explore oxide thin films to achieve memristive Efficient, Robust Oxide Switching. The main aim is to investigate novel materials characterised by anisotropic oxygen defect mobility along defined planes. Such systems can provide fast ionic conduction and cation exchange and are thus promising for reduced power consumption and higher processing speed. Thin films of high-quality oriented structures will be developed through pulsed laser deposition techniques and their composition will be monitored to enable an in-depth understanding of ionic conduction and resulting resistive switching (RS). The control of cation motion along predefined directions or crystallographic paths will permit precise regulation of RS to make it uniform and robust. This will then be utilised for volatile and non-volatile memorisation for neuromorphic computing applications. The main aim is the elimination of RS stochasticity which is common in many emerging RS technologies and which constitutes one of the major bottlenecks toward reliable cyclability and reliability in memristive systems. Nanodevices developed in the EROS project can open the door to electronic properties with unprecedented scaling to fulfill industry requirements for large-scale manufacture.
The project is funded by Prof. Driscoll's Advanced ERC and the core team consists of Prof. Driscoll herself and Dr. Barbara Salonikidou. For more information on EROS, see here, for an overview of all our memory-related projects see here, and for some of our in-house capabilities see here.
Team Members
Dr Markus Hellenbrand joined the project in September 2023 after previously working on the related EPSRC-ECCS resistive switching project. He comes with a wealth of experience in electrical characterisation of resistive switching devices and depositing amorphous nanocomposite thin films, and the findings of his recent publication on these films as well as his recent review article on resistive switching in hafnium oxide will be very important puzzle pieces for the continuation of the EROS project.
Dr Max Becker worked on the project between 2022 and 2023. He is a Research Associate who performed the work under WP1.1.2 in the report. He worked on optimising the film growth of doped HfO2 and on undertaken electrical measurements and understanding of the new Schottky – Ohmic memristor behaviour that he discovered. He also worked closely with a PhD student funded from another project and mentored and encouraged him. The PhD student demonstrated excellent neuromorphic data and continues to proceed in the same direction.
Dr Barbara Salonikidou is working on the project since 2022. She is a Research Associate and has been working on resistive switching Na-doped WO3 films (WP1.1.3). The findings are going to be published early this year and presented in the '4th Workshop on Neuroengineering: brain-on-a-chip platforms' (Porto, 4-5 April 2024). She is also leading the organisation of the outreach project, where different group members participate in the Cambridge Festival, an event that aims to engage with the public on the research going on in the University, and other public engagement activities.
Dr Nives Strkalj worked on the project for 12 months, 6 months funded from the project. She started as a visitor continuing from her Swiss National Science Foundation fellowship and later joined as a Research Associate. She worked on WP3, focusing on using ferroelectric materials as resistive switching elements. Her work involved the design and characterisation of ferroelectric-based heterostructures.
Dr Thomas Rembert worked on the project in 2022. He was a Research Associate and short term visitor from Berkeley in the USA and was part funded by other funds. He worked on WP1.1.1. He worked on nanoplasmonic characterisation of doped HfO2 films to understand the role of oxygen on phase transformations and resistive switching behaviour.
Project Updates - January 2024
We are working on thin film layers based on binary oxides for efficient resistive switching devices. The ultimate target is to understand and control the oxygen and cation mechanisms during switching. The fabrication is based on low temperatures, making them compatible with the present CMOS technology. We are pleased to announce that the 30-month report is submitted successfully at the beginning of 2024! During this period a great work has been published and presented.
Examples of related publications
[1] “In Operando Optical Tracking of Oxygen Vacancy Migration and Phase Change in few Nanometers Ferroelectric HZO Memories”, Jan, A and Rembert, T. and Taper, S. and Symonowicz, J. and Strkalj, N. and Moon, T. and Lee, Y. S. and Bae, H. and Lee, H. J. and Choe, D.-H. and Heo, J. and MacManus-Driscoll, J. L. and Monserrat, B. and Di Maryino, G., Adv. Functional Materials, DOI:10.1002/adfm.202214970
[2] “Schottky-to-Ohmic switching in ferroelectric memristors based on semiconducting Hf0.93Y0.07O2 thin films”, Muller, M. L. and Becker, M. T. and Strkalj, N. and MacManus-Driscoll, J. L., Appl. Phys. Lett., 121, 2022, DOI:10.1063/5.0095762
[3] "Thin film design of amorphous hafnium oxide nanocomposites enabling strong interfacial resistive switching uniformity", M. Hellenbrand, B. Bakhit, H. Dou, M. Xiao, M. O. Hill, Z. Sun, A. Mehonic, A. Chen, Q. Jia, H. Wang, and J. L. MacManus-Driscoll, Sci. Adv. (2023). https://doi.org/10.1126/sciadv.adg1946
[4] "Multi-level resistive switching in hafnium-oxide-based devices for neuromorphic computing", M. Hellenbrand and J. L. MacManus-Driscoll, Nano Convergence 10, 44 (2023). https://doi.org/10.1186/s40580-023-00392-4
Conferences
[1] ''Ferroelectricity and Resistive Switching in BaTiO3 Thin Films with Liquid Electrolyte Top Contact for Bioelectronic Devices'', Maximilian Becker (delivered the oral presentation), Poppy Oldroyd, Nives Strkalj, Moritz Mueller, George Malliaras, Judith MacManus-Driscoll, 2022 MRS Fall Meeting, 28 Nov. 2022, Boston, U.S.
[2] “Schottky-to-Ohmic switching in ferroelectric memristors based on semiconducting”, First Cambridge Memristor Workshop, 8 Sept. 2022, Trinity College, Cambridge, UK. Presenter: Dr. Maximilian Becker, Moritz Muller
[3] “Schottky-to-Ohmic switching in ferroelectric memristors based on semiconducting”, High-K Workshop, Namlab, 12 Sept 2022, Dresden, Germany. Presenter: Dr. Maximilian Becker, Moritz Muller
Outreach
1 November 2023: Markus presented our work at the Postdocs of Cambridge Society Research Showcase. More than 50 postdocs from various backgrounds attended the event and the talk initiated many interested discussions.
10 October 2023: Markus presented our work on resistive switching and neuromorphic devices to a multidisciplinary group of postdocs of the Trinity College Postdoc Society. Link to the event news here.
14 July 2023: After publishing his article about resistive switching in amorphous hafnium oxide nanocomposite thin films, Markus was invited to the interantional science podcast 'Quantum Photonics Club'. Link to the news event here.
18 March 2023: The memory team and EROS participated in the Cambridge festival, presenting and discussing the exciting science behind developing next-generation non-volatile memory devices that aim to change the future of computing. Find out here about the Explore Materials project and more info on the Materials Science and Metallurgy participation at the Cambridge Festival. Click here for some more info and group pics!
4-5 April 2024: Barbara participated in the 4th Workshop on Neuroengineering: brain-on-a-chip platforms, where potential applications of neuromorphic and memristive devices in bioengineering are discussed.
