Reactive magnetron sputtering of copper oxide coatings using the metallic mode assisted by RF-ICP source: Experiment and calculation

This work investigates the deposition of copper oxide coatings by mid-frequency direct current magnetron sputtering in the metallic mode, enhanced by a radio-frequency inductively coupled plasma source. The influence of key technological parameters—oxygen flow rate (10–40 SCCM), target power density (15.7–39.3 W/cm2), and carousel rotation rate (0.625–5 rpm)—on the phase and elemental composition and microstructure of the coatings was studied experimentally. It was established that the coating composition is determined by the ratio of the fluxes of deposited copper atoms and oxygen particles arriving at the substrate. It was shown that the Cu2O phase forms at high values of the Cu/O flux ratio (0.04–0.23), while the CuO phase forms at low values (0.02–0.04). It was revealed that the carousel rotation rate critically affects the microstructure: At low rates (≤2.5 rpm), multilayer coatings with alternating CuO and Cu2O layers are formed, whereas at 5 rpm, an almost homogeneous CuO coating is obtained. Based on experimental and calculated data, contour diagrams were constructed to predict the phase composition of the coatings depending on the varied deposition parameters. The proposed mechanism based on modulating the fluxes of copper atoms and oxygen particles reaching the substrate through adjustments in key technological parameters offers opportunities for controlling coating properties in high-throughput industrial processes.