Simulation of lateral ion migration during electroforming process

TL;DR

This paper develops a finite element model to simulate lateral ion migration during the electroforming process in metal/oxide/metal structures, accurately replicating filament formation and composition dynamics.

Contribution

It introduces a coupled charge, heat, and mass transport model specifically for simulating filament formation in resistive memory devices.

Findings

Model accurately reproduces filament diameter and composition.

Identifies critical material parameters affecting filament formation.

Provides insights into the dynamics of ion migration during electroforming.

Abstract

Non-volatile memory devices have received a lot of interest in both industry and academia in the last decade. Transition metal oxide-based memories offer potential applications as universal memory and artificial synapses. Here we focus on the one-time conditioning of metal / oxide / metal structures leading to the formation of a conducting filament in TiN/TaxO1-x/TiN structures and develop a finite element model of this process. Model solved coupled equations for charge, heat, and mass transport with the last one including concentration, temperature, and stress gradients as driving forces. The results closely replicated available structural data such as diameter and composition of Ta-enriched core of the filament, O-enriched ring around it, and the dynamics of filament formation. The range of critical material parameters, namely heats of transport for Ta and O, is discussed.