New collective trampoline mechanism of accelerated ion-plasma sputtering

Results of the newly found anomalous accelerated plasma ion sputtering of solid-state targets are presented. The rate of sputtered particles comprises from one to several tens of atoms per one impinging ion, ion energies being in the range of tens to five hundreds electron volts. The anomalous sputtering is realized for ion current density in the plasma flow being not less than 10 mA cm⁻² and threshold specific power of the ion flow from 0.7 to 2 W cm⁻² depending on the target material. The qualitative explanation proposed dubbed 'collective trampoline accelerated sputtering'. The collective nature of this sputtering regime differs from the conventional pair collision cascade one. The trampoline sputtering leads to the intense texturing of the materials with submicron characteristic structure sizes. The new sputtering method could be applied (i) in the technology of plasma ion deposition of the functional coatings to replace the widespread magnetron sputtering sources of lower productivity; (ii) in the photovoltaics to solve the problem of the so-called 'black' multi-crystalline silicon in order to reduce the light reflectance coefficient; (iii) in the production of silicon composite anodes for lithium ion batteries to enhance their lifetimes regarding charge/discharge cycles, for which the final positive result is largely determined by the surface structure of the silicon wafer for photovoltaics and the surface structure of the anode current collector for lithium-ion batteries. (paper)