Preparation and Properties of ZnO Transparent Conductive Thin Films by Activated Reactive Evaporation Method

Zinc oxide films were prepared on silica glass substrates by the use of an r.f. activated reactive evaporation (ARE) method, and were examined by X-ray diffraction (XRD) and scanning electron microscope (SEM). The electrical conductivity of the films and the doping effect of Al ions were also investigated. XRD measurements indicate that the films were c-axis oriented and that an r.f. plasma of Zn and O was necessary for the ZnO film deposition. Substrate temperature, oxygen gas pressure, evaporation rate, r.f. power and Al doping amount affect the c-axis orientation, the growth rate, the microstructure of the films and electrical conductivity. Optimum conditions with a fine texture of the surface and having good ctystallinity as well as good conductivity (≒10(-4)Ω・cm) were as follows : the substrate temperature; 200℃, the total evaporation rate; 1.0Å/s, the oxygen pressure; 2.0×10(-4) Torr, the r.f. power; 250W and the Al evaporation rare ratio; 2～6%. The films with 1.0×10(-3)Ω・cm were prepared at 50℃ for the substrate temperature