A novel technique for the deposition of aluminium-doped zinc oxide films

Aluminium-doped zinc oxide is used in many applications as a transparent conductive oxide coating. Such coatings are often deposited by DC reactive sputtering of metallic targets, or RF sputtering of ceramic targets. Both of these techniques have their limitations. In the DC case, alloy targets are expensive and only allow a single composition per target. Additionally, in the RF case, targets produced by hot-pressing, or sintering may have a tendency to crack unless sputtered at low powers, thus restricting the deposition rate. However, sputtering from blended powder targets offers a potential solution to all of these problems. In this project, therefore, a series of Al-doped ZnO films have been produced by the pulsed DC magnetron sputtering of blended ZnO/Al2O3 powder targets. Initial results, presented here, indicate that high quality, defect-free films can be produced with suitable electrical and optical properties. The crystallinity of the films has been examined by X-ray diffraction, before and after annealing in controlled atmospheres. A thorough investigation of glass substrate cleaning techniques has also been carried out, with the effectiveness of each technique being assessed in terms of the coating-to-substrate adhesion, as measured by the scratch testing method. (C) 2002 Elsevier Science B.V. All rights reserved.