Self-consistent continuum-based transient simulation of electroformation of niobium oxide-tantalum dioxide selector-memristor structures

Abstract

Transient electroformation simulation of niobium oxide selectors, self-aligned to tantalum dioxide memristor structures, is described by a computational solution of the mass transport equation self-consistently coupled to the heat and electronic charge transport equations. Augmentation of an electrothermal drift-diffusion formulation by a thermally activated field-enhanced mass transport term self-consistently describes transient evolution ab initio of electric potential, temperature, and charge carrier density to model electroformation of our niobium oxide-tantalum dioxide selector-memristor structure. The present formulation requires no a priori current filament model. Simulated transient electroforming behavior of our as-fabricated self-aligned selectors illustrates that transient evolution of niobium oxide to its stable metallic phase produces a decrease in localized resistivity, initiating a self-limiting effect on spontaneous electroformation, suggesting a method to finely tailor electroformation processes by explicitly tuning pre-fabrication device design and post-fabrication electrical operations for optimum initial conditioning of selector structures.