Optical diagnostics of the magnetron sputtering process of copper in an argon–oxygen atmosphere

In this paper, a diagnostic tool for magnetron sputtering deposition of copper oxides is presented. The copper oxide thin films were deposited in DC-MF mode for various argon/oxygen mixtures, including deposition in a pure oxygen atmosphere (fully reactive mode). The copper oxides were deposited on quartz glass substrates and carbon foils. The deposition process was monitored using optical emission spectroscopy. The films were further analysed by X-ray diffraction (XRD), optical measurements, and Rutherford backscattering spectroscopy (RBS). The obtained results confirmed that optical emission spectroscopy (OES) can be used as a diagnostic tool for magnetron sputtering technology that enables control of the sputtering mode, and therefore, the deposition of pure metallic (Cu) and various oxide (Cu2O, CuO) films can be performed. The results show that by increasing oxygen content in the argon/oxygen mixture, the sputtering rate is reduced; however, in the oxygen, at 40–100% range, it is stabilised at 12 nm/min.