Microscopic Structure and Dynamic Study in Amorphous InGaZnO Focusing on Oxygen-Centered Complex

Abstract

Amorphous InGaZnO (a-IGZO) has been widely studied for its excellent electrical properties and stable amorphous structure, making it suitable for various electrical devices. Using molecular dynamics simulations, we investigated its subnanoscale structure and dynamics, especially focusing on O atoms and its local environment. A previously developed force field was used for all-atomic simulations, allowing us to study various oxygen-centered complexes (OCCs). We analyzed the coordination structures using radial distribution functions and nearest neighbor analysis to identify the characteristics of each metal element when it was coordinated with the O atoms. The OCCs were categorized, and their populations and compositions were investigated. The lifetimes of the OCCs were calculated as a function of temperature, providing insights into their stability. The conditional probabilities of the OCC transitions were calculated, identifying two distinct groups based on the presence or absence of another O atom. Differences in the dynamics of the O atoms within these groups were observed, where O atoms with another O atom in complexes exhibit faster speeds and larger mean squared displacements. These findings contribute to a deeper understanding of a-IGZO's fundamental properties and potential applications in electronic devices such as DRAM and displays.