High-Rate Zn Thin Films Deposition from Cluster Plasma of a Low-Pressure Arc

A high pressure of saturated zinc vapor (10–100 Pa) was achieved by anodic evaporation of zinc in an arc with a self-heated cathode at low discharge currents of 2–4 A and an argon pressure of 1 Pa. The deposition rate of Zn films from the expanding vapor flow reached 2 μm/min at a distance of 100 mm from the crucible. To determine the composition of the plasma flow, neutral and charged particles of the flow were separated using a grid probe with a retarding field and an electrical measurement of the ion current on a flat probe was performed. From a comparison of the results of gravimetric and electrical measurements, it follows that the deposited zinc films are formed mainly by a flow of positively charged clustered zinc ions, the average number of atoms in which increases with increasing discharge current up to ~10. The surface morphology and structure of the obtained films were studied by atomic force microscopy and X-ray diffraction.