RESISTIVE SWITCHING IN TIO2 FOR MEMORY APPLICATIONS

Abstract

Resistive switching refers to the electrically stimulated change of resistance under the action of an electrical field or current. Among many resistive switching materials, TiO2 has drawn widespread attention. As the system is complex, there are many experimental and theoretical challenges in exploring the underlying mechanisms. It has been proposed that the resistance switching mechanisms can be categorized into the filamentary type and the interfacial type. Both types of mechanisms have been reported in different material systems. In this dissertation, we propose an integrated model, and perform supporting experimental and theoretical studies. Multiple filamentary characteristics are also investigated. We report the observation of symmetrical negative differential resistance (NDR) characteristic with high repeatability in a switching device. Based on first-principles modeling and experimental measurements, we propose a new understanding of the Simmons and Verderber (SV) mechanism for charge storage, incorporating oxygen molecular ions into the model.