High-rate deposition of ZnO thin films by vacuum arc plasma evaporation

Transparent and conductive Al- or F-doped ZnO (AZO or FZO) thin films were prepared by a vacuum arc plasma evaporation method using oxide fragments. A resistivity of 5.8×10−3 Ω cm was obtained in an AZO film deposited with an Al2O3 content of 10 wt %. However, it was found that doping Al into ZnO films was very difficult because of the large difference in decomposition energy (vapor pressure) between Al2O3 and ZnO. In FZO film depositions, the electrical and optical properties could be controlled by varying the ZnF2 content. Highly conductive and transparent FZO films were prepared on low-temperature substrates with the introduction of O2 gas during the deposition. A low resistivity of 7.4×10−4 Ω cm and an average transmittance above about 78% in the visible wavelength range were obtained in a FZO film deposited at a substrate temperature of 100 °C. A high deposition rate of 180 nm/min was obtained in films deposited on large area substrates with a cathode plasma power of 6.0 kW.