Investigation on anomalous dependence of structure and optical-electrical properties on substrate temperature in RF magnetron sputtered ITO films
摘要
The study on influence of substrate temperature (Ts) on ITO film’s characteristics is particularly crucial, both for understanding its transparent conductive properties and for practical applications. This study reports an anomalous relationship between ITO film’s resistivity and Ts—where resistivity initially increases and then decreases with rising Ts from RT to 400 °C (reaching highest at 100 °C), which significantly deviates from the commonly observed trend of first decreasing and then increasing. Through XPS analysis of elemental chemical states in both the film and target, the underlying mechanism for this anomalous behavior was elucidated. Additionally, results reveal (400) and (211) preferred orientations for films deposited at RT and 50 ~ 400 °C, respectively. As Ts rises, the crystallite size first increases, then slightly decreases or stabilizes, and finally increases again. Increasing Ts induces varied surface morphologies and initially increases and then decreases surface roughness. RT-deposited film exhibits inferior conductive stability in damp-heat environment. Increasing Ts generally enhances optical transmittance, but excessively high Ts reduces transmittance. These findings also differ from those reported in previous studies. This research contributes to a deeper understanding of the Ts dependence of characteristics of ITO films and provides guidance for preparing high-performance ITO films.