Multiphysics-Coupled Ionic Migrations in Understanding Resistive Switching of Oxygen Vacancy-Based Resistive Random Access Memory (RRAM)

The ionic transportation process is the main driving mechanism in novel microelectronic devices, such as resistive random access memories (RRAMs) and ionic-gated transistors. Understanding the ionic migration under multiple coupled physical fields provides valuable information and guidelines for device design and optimization. The oxygen vacancies transportation processes include drift under an electric field, Fick diffusion under a concentration gradient, and Soret diffusion or thermophoresis under a temperature gradient, where the last effect is often neglected. The working mechanism of RRAM devices depends on the conductive filament formation and rupture inside the resistive switching (RS) layer. The reliability and uniformity issues of RRAM devices come from the complex ionic transportation in amorphous materials under multiple coupled physical fields. In this work, we propose a technology computer-aided design (TCAD) model for RRAM devices that includes the full ionic transport mechanisms as well as takes the ionic generation and recombination processes into consideration. Based on this model, we investigated the effect of different parameters on device behavior.