Preparation of aluminum-doped zinc oxide thin films using an embedded-zinc ZnO(Al) target

Abstract

Aluminum-doped zinc oxide (ZnO(Al)) thin films were deposited by RF magnetron sputtering on unheated soda-lime glass substrates using embedded-Zn ZnO(Al) targets with different Zn contents of 0, 1, 3 and 6 wt%. The structural characteristics of the films were investigated by X-ray diffractometry (XRD), while the electrical properties and the optical properties were studied by the Hall effect measurement and optical transmission, respectively. All of the deposited films show a preferred (002) orientation with c-axis perpendicular to the substrate. It was found that crystallinity of the films decreases with increasing RF sputtering power. The lowest electrical resistivity of the order of 10[superscript -3] Ωֹ̇̇cm was obtained and strongly affected by the preparation conditions, especially the RF power and the Zn content in the target. The transparency of the films deposited from these targets shows the average transmission within the visible range being 90%. Moreover, the Zn content in the target can cause an increase in transmission, but also a reduction in the conductivity of the films. In this research, at Zn content of 1 wt% embedded into ZnO(Al) target, the deposited films yield low resistivity and high transparency which is suitable for transparent conductive thin films.