title: Element- and charge-state-resolved ion energies in the cathodic arc plasma from composite AlCr cathodes in argon, nitrogen and oxygen atmospheres.
abstract: The energy distribution functions of ions in the cathodic arc plasma using composite AlCr cathodes were measured as a function of the background gas pressure in the range 0.5 to 3.5 Pa for different cathode compositions and gas atmospheres. The most abundant aluminium ions were Al+regardless of the background gas species, whereas Cr2+ions were dominating in Ar and N2and Cr+in O2atmospheres. The energy distributions of the aluminium and chromium ions typically consisted of a high-energy fraction due to acceleration in the expanding plasma plume from the cathode spot and thermalised ions that were subjected to collisions in the plasma cloud. The fraction of the latter increased with increasing background gas pressure. Atomic nitrogen and oxygen ions showed similar energy distributions as the aluminium and chromium ions, whereas the argon and molecular nitrogen and oxygen ions were formed at greater distance from the cathode spot and thus less subject to accelerating gradients. In addition to the positively charged metal and gas ions, negatively charged oxygen and oxygen-containing ions were observed in O2atmosphere. The obtained results are intended to provide a comprehensive overview of the ion energies and charge states in the arc plasma of AlCr composite cathodes in different gas atmospheres as such plasmas are frequently used to deposit thin films and coatings.
authors.affiliation: Montanuniversität Leoben, Franz-Josef-Strasse 18, 8700 Leoben, Austria ; Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Franz
authors.affiliation: PLANSEE Composite Materials GmbH, Siebenbürgerstrasse 23, 86983 Lechbruck am See, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Polcik
authors.affiliation: Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.
authors.forename: André
authors.initials: A
authors.lastname: Anders
keywords: AlCr; Background gas; Cathodic arc; Composite cathode; Ion energy distribution function