Oxygen flow rate effect on copper oxide thin films deposited by radio frequency magnetron sputtering

Copper oxide thin films are prepared by radio frequency magnetron sputtering technology. The analysis of the deposited films by X-Ray Diffraction (XRD), spectrometry and electrical resistivity measurements is carried out. The results show that the working pressure and O2 flow rate have a crucial impact on copper oxides films properties. The apparition of the main copper oxides CuO and/or Cu2O phases is affected by the experimental plasma parameters, mainly the O2 flow rate. The presence of multiple peaks on XRD patterns indicates the polycrystalline nature of the deposited films. At higher O2 flow rate, single-phase composed of crystallized CuO is formed. While at lower O2 flow rate the films are two-phase (CuO and Cu2O). The study of the plasma discharge by optical emission spectrometry as function of O2 flow rate, at given pressure and power supply, is essential to find the best operating range to tune the correct stoichiometry and phases, giving therefore the preferred properties for a specific application.