Physical properties and etching characteristics of metal (Al, Ag, Li) doped ZnO films grown by RF magnetron sputtering

Metal doped ZnO (MZO, metal = Al, Ag, Li) films were deposited by RF magnetron sputtering system. We investigated the physical properties and the etching characteristics of the MZO films. All MZO films have shown a preferred orientation in the [001] direction. As amounts and a kind of dopant in the target were changed, the crystallinity and the transmittance as well as the optical band gap were changed. The electrical resistivity was also changed according to the metal doping amounts and a kind of dopant. The chemical dry etching of as-grown MZO thin films was investigated by varying gas mixing ratio of CH4/(CH4 + H2 + Ar) and additive Cl2 chemistries. We could effectively etch not only a zinc oxide but also metal dopant using methane, hydrogen, argon, as well as chlorine gas. Changes of the structural, optical electrical properties, etch rate, and chemical states of etched surface for the MZO films were also explained with the data obtained by SEM, XRD, UV, 4-point-probe and XPS analyses.