Deposition of aluminum-doped zinc oxide films by RF magnetron sputtering and study of their surface characteristics

Transparent conductive, undoped and aluminum-doped ZnO (AZO) thin films were prepared on the glass substrates at deposition temperature in the range of room temperature (R.T.) ∼300 °C by RF magnetron sputtering. Highly oriented AZO films in the [002] direction were obtained with specifically designed ZnO targets. A systematic study on the dependence of deposition parameters on the structural, optical and electrical properties of the as-grown AZO films was mainly investigated in this work. The AZO film prepared at R.T. with 4 wt.% Al(OH)₃ doped a ZnO target under a target-to-substrate distance (D_ts) of 45 mm, has not only a high transmittance of 85% at the visible region but has also a resistivity of 9.8 × 10^-2 Ω·cm. In addition, the resistivity of AZO films increases with increasing T_sub. We investigated that this tendency was altered after 4 wt.% doping.