Aluminum-doped zinc oxide thin films prepared by reactive dc magnetron sputtering with metal, transition, and oxide modes

Abstract

In this work, the aluminum-doped zinc oxide (AZO) thin films were prepared using the reactive direct current (DC) magnetron sputtering. The Zn/Al alloy with 2 wt% of aluminum and 2 inch of diameter was used as a target. The glass slide and p-type Si (100) wafer were used as a substrate. The deposition time of 5 min, power of 150 W, and argon flow rate of 10 sccm were used as the controlled parameter. While the discharge voltage and the oxygen flow rate were adjusted corresponding to the metal, transition, and oxide modes. The electrical and optical properties of AZO thin films were characterized by Hall effect measurement and ultraviolet-visible-infrared spectroscopy, respectively. It is found that the AZO thin films prepared by the discharge voltage of 370-380 V and the oxygen flow rate of 4.32-4.42 sccm which is corresponding to oxide mode gives the highest value of figure of merit. This result shows that the film has the highest ratio of the optical transmission and sheet resistance. The structural property of the AZO thin films was characterized by X-ray Diffraction (XRD). It is observed that the AZO thin films are predominantly oriented at c-axis (002) and achieved high crystalline quality.