Influence of Deposition Pressure on Properties of ZnO: Al Films Fabricated by RF Magnetron Sputtering

Transparent conductive aluminum doped zinc oxide (ZnO: Al, AZO) films were prepared on glass substrates by rf (radio frequency) magnetron sputtering from ZnO: 3wt% Al2O3 ceramic target. The effect of argon gas pressure (P (Ar)) was investigated with small variations to understand the influence on the electrical, optical and structural properties of the films. Structural examinations using X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that the ZnO: Al thin films were (002) oriented. The resistivity values were measured by four-point probe with the lowest resistivity of 5.76x10(-4) Omega.cm (sheet resistance=9.6 Omega/sq. for a thickness=600 nm) obtained at the P (Ar) of 0.3 Pa. The transmittance was achieved from ultraviolet-visible (UV-VIS) spectrophotometer, 84% higher than that in the visible region for all AZO thin films. The properties of deposited thin films showed a significant dependence on the P (Ar).