Film properties of ZnO:Al films deposited by co-sputtering of ZnO:Al and contaminated Zn targets with Co, Mn and Cr

Influence of Co, Mn and Cr contaminants were investigated in transparent conductive ZnO:Al films in the co-sputtering of ZnO:Al and Zn targets. The addition of extra Zn in this process was effective in decreasing film resistivity. However, the resistivity of as-grown ZnO film showed a rapid increase at 100degreesC annealing in air. This was attributed to the incorporation of oxygen at boundaries of columnar micro crystals of ZnO:Al. The inclusion of contaminants such as Co, Mn and Cr was observed to cancel the Zn-doping effect for as-grown ZnO:Al films, but stabilized the resistivity change under oxygen exposure. The film with Cr doping was stable below 400degreesC, and showed nearly a constant of about 7 x 10(-4) Omega cm. (C) 2002 Elsevier Science Ltd. All rights reserved.