Ab-initio Study on Oxygen Defect of Metal Oxides (TiO2, Ta2O5) for Resistive RAM

Abstract

Recently, Resistive Random Access Memory (ReRAM) has rapidly fascinated, as it is now regarded as the promising applicant for the next-generation of memory device, due to its high density, low operating power, fast switching speed, and compatibility with the conventional complementary semiconductor process. The resistive switching is strongly related with the presence and dispersion of oxygen vacancies involving the formation of a conductive filament. Although many researchers have studied to address the resistive switching mechanism during the last decade, it is hard to understand what mechanism happens inside the device. In this dissertation, a theoretical study of Metal oxides (TiO2, Ta2O5) materials using ab-initio methods based on density functional theory (DFT) is studied. These materials are well known as resistive switching materials. The bulk properties and el ectronic properties of the transition metal oxide emiconductor systems were intensively investigated. Density of states, band decomposed charge density distribution, energy band structure and lattice parameters were calculated. Based on the results, resistive switching model can be well described using DFT. The results are valuable for the explanation of the resistive switching mechanism.