Resistive Switching in Oxides

Abstract

Resistive switching in oxides, the phenomenon whereby the resistance of samples of the matrix can be cycled between states with contrasts of up to several orders of magnitude, has received growing attention over the past decade thanks to the possibility of exploiting this effect in novel memory technologies. Here we summarise the current state of the art in the field, paying particular attention to the underlying mechanisms of switching, which involves the creation of defects in the oxide. We also describe potential technological applications. IntroductionRecent years have seen a rapid growth of interest in materials whose electrical resistance can be changed by the application of an electric field. Of course, the phenomenon of irreversible electrical breakdown (so-called "hard breakdown") in oxides has long been studied as a failure mechanism in microelectronics-initially in capacitors and high voltage devices, then in thin films in integrated microelectronics-and, as such, is of great interest to industry as a problem to be mitigated. However, the resistive switching we refer to here is a reversible process whereby material can be cycled between two or more resistance states many times, enabling non-volatile memory technologies. Because of the range of potential technological applications-from replacements for existing technologies such as flash, to novel neuromorphic (neuron-mimicking) systems-resistive switching is now seen as an opportunity rather than a problem, and academic and industrial interest has grown to the point at which there are several hundred publications per year on all aspects of resistive switching materials and devices. Although we will not discuss fundamental issues associated with defect formation on oxides, these can be found in other chapters in the volume.

The interplay between structure and function in redox-based resistance switching

“…10,11 In the case of lamentary switching, an initial electroforming step is generally required in which the extremely high resistivity pristine oxide undergoes a permanent change to generate one or more conductive la-ments. It is worth noting that it is possible to engineer defects in pristine devices in a way that makes electroforming unnecessary.…”

Complementary Metal‐Oxide Semiconductor and Memristive Hardware for Neuromorphic Computing

“…Many different mechanisms could govern the resistance switching in silicon oxide. Generally, the filamentary resistance switching mechanisms are classified into those that are intrinsic to the oxide material—commonly known as valance change or intrinsic switching mechanisms—and those that involve metallic diffusion from electrochemically active electrodes (e.g., silver or copper) or metal doping to form metallic filaments—commonly known as electrochemical metalization, conductive bridge, or extrinsic switching mechanisms …”

Investigation of resistance switching in SiOxRRAM cells using a 3D multi-scale kinetic Monte Carlo simulator

“…Several RRAM technologies are nowadays under investigation. In this context, oxide-based RRAMs represent one of the most studied devices; materials of interest include metal oxides [13], such as TiOx and HfOx, and SiOx [1], [20], [21]. There is also a huge interest in RRAMs based on phase-change materials, such as perovskite materials, Ge sulphide and selenide, and chalcogenides [10], [22], [23].…”