Diffusion Behaviors and Electrical Properties in the In-Ga-Zn-O Thin Film Deposited by Radio-frequency Reactive Magnetron Sputtering

Abstract

We investigated the diffusion behaviors, electrical properties, microstructures, and composition of In-GaZn-O (IGZO) oxide thin films deposited by radio frequency reactive magnetron sputtering with increasing annealing temperatures. The samples were deposited at room temperature and then annealed at 300, 400, 500, 600 and 700 o C in air ambient for 2 h. According to the results of time-of-flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy, no diffusion of In, Ga, and Zn components were observed at 300, 400, 500, 600 o C, but there was a diffusion at 700 o C. However, for the sample annealed at 700 o C, considerable diffusion occurred. Especially, the concentration of In and Ga components were similar at the IGZO thin film but were decreased near the interface between the IGZO and glass substrate, while the concentration of Zn was decreased at the IGZO thin film and some Zn were partially diffused into the glass substrate. The high-resolution transmission electron microscopy results showed that a phase change at the interface between IGZO film and glass substrate began to occur at 500 o C and an unidentified crystalline phase was observed at the interface between IGZO film and glass substrate due to a rapid change in composition of In, Ga and Zn at 700