Effect of incident angle of target molecules on electrical property of Al-doped ZnO thin films prepared by RF magnetron sputtering

About 2 wt.% Al2O3 doped ZnO thin films were prepared by using radio-frequency magnetron sputtering method. The electric property of the films was found to be heavily dependent on the incident angle of the sputtered particle, which is defined by the lateral distance of the substrate against the target center. With higher incident angle of the target particles arriving at the substrate, the electrical conductance of the film was improved by a factor of 5 and the film resistivity showed 1 × 10−3 Ω cm. The preferred orientation of ZnO(0 0 0 2) crystal plane of the film deposited at various angles were found to be inclined as much as 0.7°–4.6° against the surface normal and showed to run parallel to the incident direction of target particles.