Micro/nanomechanical properties of aluminum-doped zinc oxide films prepared by radio frequency magnetron sputtering

Aluminum-doped zinc oxide (ZnO) was grown on glass substrates by using RF magnetron sputtering. In order to investigate the effect of growth temperature on the mechanical properties of Al-doped ZnO films, the temperature of the substrates during deposition was controlled at room temperature (R.T.), 150 °C, and 300 °C. The crystal structure and topography of the deposited films were investigated by X-ray diffraction (XRD) and Atomic Force Microscopy (AFM). The mechanical properties of films were measured by using nanoindentation and micro-reciprocating pin-on-plate tester to characterize the hardness, modulus, and tribological behavior. The tribological behavior of silicon (100) wafer was also obtained to compare with that of the Al-doped ZnO. It was found that Al-doped ZnO films with (002) oriented plane was favored at high growth temperature. The mechanical properties of the films were significantly affected by growth temperature. The film grown at room temperature showed a relatively low friction coefficient of 0.25 and high wear resistance.