RF magnetron sputtering of silver thin film in Ne, Ar and Kr discharges—plasma characterisation and surface morphology

• Published in: Surface & coatings technology 2013-08, Vol.228, p.S466-S469
• Main Authors: Novotný, Michal, Bulíř, Jiří, Pokorný, Petr, Lančok, Ján, Fekete, Ladislav, Musil, Jindřich, Čekada, Miha
• Format: Article
• Language: English
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Magnetron sputtering; Mass spectrometry; Materials science; Metals. Metallurgy; Methods of deposition of films and coatings; film growth and epitaxy; Optical emission spectroscopy; Physics; Plasma characterisation; Production techniques; Silver; Surface treatment; Surface treatments
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2012.05.024

We have carried out a systematic study of the influence of Ne, Ar and Kr working gases on both plasma and film properties of RF magnetron sputtering of silver. The magnetron plasma was characterised by optical emission spectroscopy (OES) and mass spectrometry. Silver thin film morphology was examined by SEM and AFM. We studied influence of magnetron power and working gas pressure on the plasma composition. The magnetron power was varied from 25 to 100W. The ambient pressure was changed from 0.5Pa to 3Pa. Both mass and OES spectra revealed presence of highly excited plasma in the substrate vicinity for all sputtering gases. The increasing OES signal intensities of Ag and Ag+ with increasing RF power and gas pressure were observed. However, in Ar discharge there was no Ag+ signal detected by OES at lower pressures of 0.5Pa and 1Pa. Similar profiles of the energy distributions of the ions with a maximum located around 19eV were obtained in Ar and Kr discharges at pressure of 3Pa while a maximum at 28eV was measured in Ne discharge. Ag2+ and AgX+ radicals, where X is atom of particular inert-working gas, were observed in the mass spectra. Silver thin film deposited in Ne gas revealed lower roughness than the films deposited in the other gases. ► Silver thin film was prepared by magnetron sputtering in Ne, Ar and Kr discharges. ► Plasma properties were characterised by mass and optical emission spectroscopy. ► Ag+ ions exhibited higher energy in Ne discharge. ► Silver film roughness was improved in Ne gas discharge.