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Title: Magnetic dipole discharges. I. Basic properties

A simple discharge is described which uses a permanent magnet as a cold cathode and the metallic chamber wall as an anode. The magnet's equator is biased strongly negative, which produces secondary electrons due to the impact of energetic ions. The emitted electrons are highly confined by the strong dipolar magnetic field and the negative potential in the equatorial plane of the magnet. The emitted electrons ionize near the sheath and produce further electrons, which drift across field lines to the anode while the nearly unmagnetized ions are accelerated back to the magnet. A steady state discharge is maintained at neutral pressures above 10{sup −3} mbar. This is the principle of magnetron discharges, which commonly use cylindrical and planar cathodes rather than magnetic dipoles as cathodes. The discharge properties have been investigated in steady state and pulsed mode. Different magnets and geometries have been employed. The role of a background plasma has been investigated. Various types of instabilities have been observed such as sheath oscillations, current-driven turbulence, relaxation instabilities due to ionization, and high frequency oscillations created by sputtering impulses, which are described in more detail in companion papers. The discharge has also been operated in reactive gases and shownmore » to be useful for sputtering applications.« less
Authors:
;  [1] ; ; ;  [2]
  1. Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States)
  2. Institute for Ion Physics and Applied Physics, University of Innsbruck, A-6020 Innsbruck (Austria)
Publication Date:
OSTI Identifier:
22220685
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 20; Journal Issue: 8; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANODES; CATHODES; CURRENTS; ELECTRONS; GLOW DISCHARGES; LANGMUIR PROBE; MAGNETIC DIPOLES; MAGNETIC FIELDS; MAGNETIC MOMENTS; MAGNETRONS; PERMANENT MAGNETS; PLASMA INSTABILITY; PLASMA SHEATH; PLASMA WAVES; SPUTTERING; TAIL IONS