From stochastic single atomic switch to nanoscale resistive memory device

TL;DR

This paper investigates nanoscale ionic switches, demonstrating that reliable, reproducible resistive switching occurs in junctions larger than 3 nm, with potential applications in nonvolatile memory devices.

Contribution

It identifies a size threshold of 3 nm for reliable ionic nano-switches and characterizes their switching behavior, advancing the development of nanoscale resistive memory.

Findings

Reproducible switching in junctions larger than 3 nm

Random switching behavior in atomic-sized junctions

Formation and destruction of nanoscale channels in ionic conductors

Abstract

Solid state ionic conductors are good candidates for the next generation of nonvolatile computer memory elements. Such devices have to show reproducible resistance switching at reasonable voltage and current values even if scaled down to the nanometer sizes. Here we study the switching characteristics of nanoscale junctions created between a tungsten tip and a silver film covered by a thin ionic conductor layer. Atomic-sized junctions show spectacular current induced switching characteristics, but both the magnitude of the switching voltage and the direction of the switching vary randomly for different junctions. In contrast, for somewhat larger junctions with diameters of a few nanometers a well defined, reproducible switching behavior is observed which is associated with the formation and destruction of nanoscale channels in the ionic conductor surface layer. Our results define a low size limit of 3 nm for reliable ionic nano-switches, which is well below the resolution of recent lithographic techniques.