Zinc oxide-based transparent conductive oxide films prepared by pulsed magnetron sputtering from powder targets: Process features and film properties

Abstract

The pulsed magnetron sputtering of transparent conductive oxide (TCO) films from powder targets is a promising technique, which produces films with dense columnar, defect-free structures and optical and electrical properties comparable to other deposition techniques. The targets are formed from loosely packed oxide powder blends, and no additional processes, such as sintering, are required. This preparation method allows target composition and, therefore, film composition (a key parameter in TCO coatings) to be readily varied. The flexibility of this approach was exploited to produce a series of doped zinc oxide coatings, in which both the dopant level (1–5at.%) and the dopant material (Al, Sn, In, Sb, or Ga) were varied systematically. The structures and properties of these coatings were analyzed and measured using a range of techniques, including electron microscopy, spectrophotometry, x-ray diffraction, four-point probe, and Van der Pauw’s method. The TCO coatings were deposited in a rig specially designed for this purpose, and the impact of specific design features on the coating structures and properties are also considered.