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Title: Elementary surface processes during reactive magnetron sputtering of chromium

The elementary surface processes occurring on chromium targets exposed to reactive plasmas have been mimicked in beam experiments by using quantified fluxes of Ar ions (400–800 eV) and oxygen atoms and molecules. For this, quartz crystal microbalances were previously coated with Cr thin films by means of high-power pulsed magnetron sputtering. The measured growth and etching rates were fitted by flux balance equations, which provided sputter yields of around 0.05 for the compound phase and a sticking coefficient of O{sub 2} of 0.38 on the bare Cr surface. Further fitted parameters were the oxygen implantation efficiency and the density of oxidation sites at the surface. The increase in site density with a factor 4 at early phases of reactive sputtering is identified as a relevant mechanism of Cr oxidation. This ion-enhanced oxygen uptake can be attributed to Cr surface roughening and knock-on implantation of oxygen atoms deeper into the target. This work, besides providing fundamental data to control oxidation state of Cr targets, shows that the extended Berg's model constitutes a robust set of rate equations suitable to describe reactive magnetron sputtering of metals.
Authors:
; ;  [1]
  1. Research Group Reactive Plasmas, Ruhr-University Bochum, Universitystr. 150, 44801 Bochum (Germany)
Publication Date:
OSTI Identifier:
22492765
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 13; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ARGON IONS; BEAMS; CHROMIUM; CRYSTALS; DENSITY; EFFICIENCY; EQUATIONS; ETCHING; KNOCK-ON; MAGNETRONS; MICROBALANCES; MOLECULES; OXIDATION; PLASMA; PULSES; QUARTZ; SPUTTERING; SURFACES; THIN FILMS