Effect of electrode materials on resistive switching behaviour of NbOx-based memristive devices

Abstract

Memristive devices that rely on redox-based resistive switching mechanism have attracted great attention for the development of next-generation memory and computing architectures. However, a detailed understanding of the relationship between involved materials, interfaces, and device functionalities still represents a challenge. In this work, we analyse the effect of electrode metals on resistive switching functionalities of NbOx-based memristive cells. For this purpose, the effect of Au, Pt, Ir, TiN, and Nb top electrodes was investigated in devices based on amorphous NbOx grown by anodic oxidation on a Nb substrate exploited also as counter electrode. It is shown that the choice of the metal electrode regulates electronic transport properties of metal–insulator interfaces, strongly influences the electroforming process, and the following resistive switching characteristics. Results show that the electronic blocking character of Schottky interfaces provided by Au and Pt metal electrodes results in better resistive switching performances. It is shown that Pt represents the best choice for the realization of memristive cells when the NbOx thickness is reduced, making possible the realization of memristive cells characterised by low variability in operating voltages, resistance states and with low device-to-device variability. These results can provide new insights towards a rational design of redox-based memristive cells.

Hydrogen-triggered metal filament rupture in Cu-based resistance switches

“…In recent years, resistance switches have been considered to be one of the most promising candidates as the next generation memory cells and neuromorphic devices, mainly due to their low power consumption, high read/write speed, size scalability and other advantages [ 1–4 ]. Resistance switches are composed of sandwich structure (electrode/insulator/electrode), in particular, the devices with the amorphous metal oxides (such as TaO x [ 5 ], NbO x [ 6 ], HfO x [ 7 ], AlO x [ 8 ]) as the insulator layer show excellent performance. The resistive switching processes of such devices are mainly due to the diffusion of active ions (such as metal cations, oxygen anions or positive charged oxygen vacancies) in the insulator layer under the electric field and/or Joule heating effects, which results in the formation (low resistance state, SET) or rupture (high resistance state, RESET) of conductive filaments (CF) between two electrodes [ 8–10 ].…”

Adaptive Scalpel Scanning Probe Microscopy for Enhanced Volumetric Sensing in Tomographic Analysis

“…To this end, we utilize a valence change memory (VCM) cell as a reference material system exploiting the conductive filament (CF) inside a 15 nm thin NbO x layer as a structure to reconstruct. [13,14] Detail of the device VCM fabrication is mentioned in the experimental section. It is worth mentioning that these devices have been used as reference material systems due to having clean bottom electrode/metal oxide interface and amorphous material with no grain boundaries.…”