Influence of Sputtering Power and Substrate Temperature on Properties of Al2O3-Doped ZnO Films
Aluminum oxide-doped zinc oxide (AZO) films were deposited by radio frequency (RF) magnetron sputtering at various substrate temperatures and sputtering powers with pure argon flow. Their electrical and optical properties and microstructures were investigated by X-ray diffractometer (XRD), atomic force microscope (AFM), ultraviolet-visible spectrophotometer, four-probe tester. The investigation indicates that the electrical and optical properties and microstructures of the AZO films are remarkably influenced by substrate temperature and sputtering power. With the sputtering power increasing from 60W to 180W, the diffraction peaks rise significantly, the resistivity decreases quickly and the visible transmission is all quite high. When the substrate temperature increases from 25°C to 400°C, the diffraction peaks rise first and lower then both quickly, the resistivity decreases first sharply and then very slowly, and the visible transmission is also high. The films deposited at the substrate temperature 300°C with the sputtering power 180W have low resistivity 1.2×10–3 Ω•cm and high transmittance 92% at the same time.