Stateful characterization of resistive switching TiO2 with electron beam induced currents

TL;DR

This paper introduces electron beam induced current measurements as a novel tool to study local resistive switching mechanisms in TiO2-based memristive devices, providing detailed insights into filament formation and device behavior.

Contribution

The study demonstrates the use of electron beam induced current microscopy combined with simulations to analyze resistive switching in TiO2, revealing new insights into filament formation and device scaling.

Findings

Electron beam induced currents can distinguish different switching states.

Filament formation correlates with morphological changes and leakage regions.

Propagation of polarization domains observed in symmetric devices.

Abstract

Metal oxide resistive switches are increasingly important as possible artificial synapses in next generation neuromorphic networks. Nevertheless, there is still no codified set of tools for studying properties of the devices. To this end, we demonstrate electron beam induced current measurements as a powerful method to monitor the development of local resistive switching in TiO2 based devices. By comparing beam-energy dependent electron beam induced currents with Monte Carlo simulations of the energy absorption in different device layers, it is possible to deconstruct the origins of filament image formation and relate this to both morphological changes and the state of the switch. By clarifying the contrast mechanisms in electron beam induced current microscopy it is possible to gain new insights into the scaling of the resistive switching phenomenon and observe the formation of a current leakage region around the switching filament. Additionally, analysis of symmetric device structures reveals propagating polarization domains.