Improvement in moisture durability of ZnO transparent conductive films with Ga heavy doping process

Moisture durability of ZnO transparent conductive films was achieved with Ga heavy doping by off-axis type rf magnetron sputtering. The resistivity of 10.9 at.% Ga-doped ZnO was 1.3 × 10−3 Ωcm and changed less than 5% of resistivity over a 9400-h reliability test at a temperature of 85 °C and humidity of 85%. The crystal structural analysis of the heavily Ga-doped ZnO films indicated that the c-axis was oriented in various directions as well as the perpendicular direction to the substrate surface. The heavily doped Ga disorders the crystal growth of ZnO films and forms a different crystal structure from conventional ZnO.