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Time-resolved measurements have been performed during dual High Power Impulse Magnetron Sputtering (dual-HiPIMS) with two cathodes in a closed magnetic field configuration. The effect of a delay between subsequent pulses on electron density, mean electron energy, and ion flux to the substrate was investigated by time-resolved diagnostic methods. Two different delays of 15 μs and 500 μs between subsequent pulses were investigated. The dual-HiPIMS system, operated at a repetition frequency f = 100 Hz and duty cycle of 1 %, was equipped with different metallic targets (Ti, Cu). It is shown that a delay between subsequent pulses influences the plasma parameters and can be used to control deposition processes. It was noted that target surfaces (alternately serving as a cathode/anode) are contaminated by sputtered material from the previous pulse which influences the time-evolution of the discharge parameters.

Abstract:We report the self-buckling (or peeling off) of cubic Cu 3 N films deposited by DC magnetron sputtering of a Cu target in a nitrogen environment at a gas pressure of 1 Pa. The deposited layer partially peels off as it is exposed to ambient air at atmospheric pressure, but still adheres to the substrate. The chemical composition of the thin film as investigated by means of X-ray photoelectron spectroscopy (XPS) shows a considerable surface oxidation after exposure to ambient air. Grazing incidence X-ray diffraction (GIXRD) confirms the formation of a crystalline Cu 3 N phase of the quenched film. Notable are the peak shifts in the deposited film to smaller angles in comparison to stress-free reference material. The X-ray pattern of Cu 3 N exhibits clear differences in the integral width of the line profiles. Changes in the film microstructure are revealed by X-ray diffraction, making use of X-ray line broadening (Williamson-Hall and Stokes-Fourier/Warren-Averbach method); it indicates that the crystallites are anisotropic in shape and show remarkable stress and micro-strain.

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Growth of Cu nanoparticles in a pulsed gas aggregation cluster source was studied. The cluster growth is enhanced by an energy transport inside the aggregation chamber fed by argon that is delivered in short pulses repeated with low frequency. The effect of pressure, varied during the pulse, on the cluster growth was estimated from time‐resolved measurements of mass/size cluster distribution. The cluster mass and the cluster production well correlate with pressure changes. Several stages of cluster growth during the gas‐pulse were recognized. Not only larger clusters but also significantly enhanced particle and mass fluxes were observed.