Energy distribution of negative O sup minus and OH sup minus ions emitted from YBaCuO and iron garnet targets by dc and rf magnetron sputtering

Journal Article · Sun Dec 01 00:00:00 EST 1991 · Journal of Applied Physics; (United States)

DOI:https://doi.org/10.1063/1.349848· OSTI ID:5160971

Krumme, J ^[1]; Hack, R A.A. ^[2]; Raaijmakers, I J.M.M. ^[3]

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1. Philips Research, Hamburg (Federal Republic of Germany)
2. Philips Research, Eindhoven (Netherlands)
3. Novellus Systems Inc., San Jose (California)

Energy-dispersive mass spectrometry has been used to analyze the energy distribution of O{sup {minus}} and OH{sup {minus}} species ejected from YBaCuO and iron-garnet targets by Ar{sup +}, Kr{sup +}, and Xe{sup +} bombardment in H{sub 2}- and in O{sub 2}-doped dc and rf magnetron plasmas at 0.05--4.2 Pa pressure. The orifice of the plasma monitor was at 70 mm from the erosion groove underneath the plasma ring. The energy spectra of O{sup {minus}} and OH{sup {minus}} ions are found to exhibit two major peaks: a sharp one at typically 20 eV termed A and a sharp (dc case) or broad (rf case) peak termed B at higher energies. Peak-A ions may be formed near the edge of the cathode sheath by electron attachment to sputtered neutral oxygen atoms accelerated in the remaining potential gradient of the sheath. Peak-B ions are shown to be accelerated from the target surface to kinetic energies given by the potential gradient across the cathode sheath. In the case of rf magnetron plasmas the total flux of O{sup {minus}} and OH{sup {minus}} ions associated with the peak B steeply increases with pressure up to {similar to}0.6 Pa for argon, {similar to}0.4 Pa for krypton, and {similar to}0.3 Pa for xenon, concomitant with a shift of the mean particle energy from {gt}100 eV at 0.1 Pa to {lt}35 eV at these characteristic pressures. This behavior may be explained by charge-exchange collisions within the rf sheath. At pressures beyond this maximum the total flux of negative ions declines due to electron detachment in regions remote from the plasma which may be caused by collisions with noble-gas atoms and Maxwellian electrons, and by charge transfer to positive noble-gas ions. At pressures beyond several Pa elastic scattering is the dominant loss mechanism of energetic atomic oxygen species.

• OSTI ID: 5160971
• Journal Information: Journal of Applied Physics; (United States), Vol. 70:11; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
SPUTTERING
COPPER OXIDES
GARNETS
ION EMISSION
MASS SPECTROSCOPY
YTTRIUM OXIDES
HYDROXYL RADICALS
OXYGEN IONS
QUATERNARY COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
AMINES
AMMONIUM COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
CHARGED PARTICLES
COPPER COMPOUNDS
EMISSION
IONS
MINERALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
RADICALS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SPECTROSCOPY
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties