The project

Over the past decade, the rapid development of information and communication technologies opened new horizons for artificial intelligence and green technologies. These developments challenge the state-of-the-art of nanoelectronics in demanding new hardware architectures to overcome von Neumann computing by implementing neuromorphic-type of data processing. Memristive devices have recently gained tremendous interest not only in the scientific community but also in the semiconductor industry as building blocks for hardware implementation of in-memory computing and artificial intelligence, due to their ability to emulate neuromorphic type of data processing combined with high scalability down to almost atomic scale, low power consumption (<pJ for operation) and high operational speed (ps).

The revision of the SI in 2019 represents an historic change of paradigm for metrology, defining all the SI units in terms of fundamental constants of nature. The development of new experiments and devices are now needed for correlating physical observables to the fixed defining constants, paving the way for the realization of self-calibrating systems that can independently refer to the fundamental constants of nature with zero-chain traceability. In accordance with the revised SI, memristive devices exhibiting quantized conductance levels represent promising platforms for on-chip integrated and complementary metal-oxide-semiconductor (CMOS) compatible standard of resistance, which work in air and at room temperature.

While novel materials and devices for nanoelectronics indeed offer many potential benefits, they also bring challenges for testing and characterization. As an emerging technology, memristive devices lack standardization and insights in the fundamental physics underpinning its technology, hindering their further development. Understanding and controlling resistive switching behavior at the nanoscale is therefore highly challenging and high throughput metrology is urgently required. The development of new technologies for nanoelectronics, including quantum technologies, neuromorphic computing and related metrology, is in line with the European R&D programmes “Quantum Technologies Flagship” and the “Human Brain Flagship”. For this purpose, memristive model systems need to be developed, to establish a relationship in between material properties and device functionalities.

The understanding of nanoionic processes involved in memristive devices requires i) advancements in nanoelectrical characterization techniques, ii) the development of a traceable quantification of chemical, structural and ionic/electronic properties of memristive devices and iii) the development of metrological cross-platforms measurement techniques. These are the key requirements for understanding and controlling quantized conductance effects in such devices for the realization of the standard of resistance.

1. To develop well-controlled memristive model systems for establishing a relationship between the revealed material properties and actual device functionalities. This should include the manufacturing of memristive cells by the combination of depositing functional layers, structuring methods, surface treatment and engineering supported by traceable analytical and dimensional characterisation techniques.

2. To investigate nanoionic processes by advancing reliable nanoelectrical characterization of memristive devices by using metrological scanning probe microscopies (SPMs) for probing its local electrical properties by means of traceable conductive AFM (C-AFM), scalpel C-AFM for 3D reconstruction of the memristive cells and Scanning Tunneling Microscopy (STM).

3. To develop a traceable quantification of chemical, structural and ionic/electronic properties of memristive devices through scanning microscopy (AFM, SEM), Secondary Ion Mass Spectroscopy (SIMS), X-ray Spectrometry including X-ray Diffraction (XRD) and Energy Dispersive X-ray Spectroscopy (EDS) in order to achieve nanodimensional characterization at near atomic scale of the physical mechanism of the memristive cell.

4. To develop metrological cross-platforms measurement techniques with high resolution in space (< 10 nm) and time (< ms) for investigating device dynamics by correlating the variation of chemical/structural properties to the electrical response of memristive devices in operando. To also develop a quantum-based standard of resistance for nano applications including CMOS compatible and on-chip implementable resistance standards.

5. To facilitate the take up of the technology and measurement infrastructure developed in the project by the measurement supply chain (nanometrology), standards developing organisations (IEC TC 113, Versailles Project on Advanced Materials and Standards (VAMAS) TWA 2) and end users (nanoelectronics).