Characteristics of Sn and Zn co-substituted In₂O₃ thin films prepared by RF magnetron sputtering

Sn and Zn co-substituted In₂O₃ (compositions are In_1.2(Sn_0.4-xZn_0.4+x)O₃ (x = 0, ±0.1), indium tin zinc oxide, hereafter ITZO) thin films were prepared by an RF magnetron sputtering system at room temperature. The effects of the co-substitution and the post-annealing temperature, which was conducted at 400-600°C, on their structural, optical and electrical properties of the films were examined. All of the as-deposited films were in an amorphous state. With increasing annealing temperatures, plain and Sn-rich ITZO films transferred from amorphous to polycrystalline phases, but the Zn-rich ITZO films remained in an amorphous state. Optical transmittance of all the thin films increased with the annealing temperatures, and the optical bandgap also increased with the temperatures. Carrier concentration and mobility of the thin films as a function of the annealing temperatures were also analyzed.