Аннотация:Modern plasma technologies applied for nm-size devices require localizing ions’ impact within up to atomic layer to avoid uncontrollable damage of underlying structures. The decrease in energy of ions incident on a surface is one of the ways to achieve this. In this work, SiO2 sputtering by Ar+, Kr+, and Xe+ ions at energies of 20–200 eV was studies in the low-pressure ICP-discharge at a plasma density typical for plasma processing. The rf-bias waveform tailoring due to high discharge asymmetry allowed generating and controlling ion narrow energy spectrum with FWHM 5±2 eV. Real time in-situ control over ion composition and flux as well as sputtering rate provided accurate determination of the SiO2 sputtering yield, . It is shown that at ion energy above ∼70 eV, the “classical” kinetic sputtering mechanism prevails. In this case, rapidly grows with ion energy, while decreasing with the decrease in ion mass. Below ∼70 eV, the change of is strongly slow down while the sputtering yield still stays high enough (>10-3), demonstrating the plasma impact on the sputtering mechanism. The obtained trends of under the plasma exposure are discussed in light of possible SiO2 surface modification studied by AFM and angular XPS analysis.
