Smooth indium zinc oxide film prepared by sputtering a In2O3:ZnO=95:5 target

Indium zinc oxide (IZO) films with surface roughness Ra<0.3 nm have been prepared by radio frequency sputtering. The IZO film is the possible candidate for replacing the indium tin oxide (ITO) film in pattern precision or low processing temperature concern. Instead of commonly used In2O3:ZnO=90:10 in weight percentage (wt%) target, a target doped with 5 wt% impurities was used in this study. It was found that the electrical resistivity of the IZO film increases rapidly if oxygen gas was introduced during the sputtering process. This increase tendency in electrical resistivity is much more significant than the IZO film prepared with a 10 wt% doped ZnO target. The electrical resistivity increased rapidly as soon as the IZO film became crystallized in heat treatment. Optical properties of the IZO film do not change significantly with varying process parameters. The appropriate processing condition for the prepared IZO film is no oxygen feeding and no heat treatment.