Structural characterization of zinc oxide thin films deposited at various O2/Ar flow ratio in magnetron sputtering plasma

Zinc oxide (ZnO) is one of the metal oxide semiconductors suitable for use in optoelectronic devices and a potential material for the future solar cell applications. In this works, ZnO films were deposited on silicon and glass substrate by reactive rf magnetron sputtering using a solid Zn target. The influence of the oxygen flow rate and the working pressure on the zinc oxide films microstructure were studied. The deposition power was fixed at 200 W. Crystalline structures, morphology characteristics of ZnO films were investigated by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), respectively. The XRD results showed that the ZnO (002) peak was dominant when the oxygen flow ratio was above 5%. The ZnO (102) was observed at 5 mTorr of deposition pressure but almost unseen at 10 mTorr of deposition pressure. On the other hand, the surface morphology of ZnO thin film was varied with the oxygen partial pressure.