Stoichiometry Control of ZnO Thin Film by Adjusting Working Gas Ratio during Radio Frequency Magnetron Sputtering

ZnO thin films were deposited on quartz glasses by a radio frequency (rf) magnetron sputtering. The mechanism for stoichiometry in the ZnO thin films was investigated by adjusting Ar/O2 working gas ratio during deposition. The optical emission spectroscopy (OES) in situ measurement revealed the kinetics species variation during rf plasma deposition process. It was found that the intensity of the excited atomic oxygen (O*) was increased with the oxygen ratio increasing, resulting in enhancing the oxidization effect during ZnO film fabrication. On the contrary, the intensities of atomic zinc emission were gradually decreased, resulting in the zinc ratio in the film were decreased with the oxygen ratio increasing. Therefore, it is possible to control the stoichiometry of ZnO film by simply adjusting the working gas ambient in the rf plasma deposition. The structural and optical properties of ZnO thin films were investigated as well