Experiments by Radioactive Tracer Methods on Sputtering by Rare-Gas Ions

Journal Article · Tue Feb 06 04:00:00 EST 1962 · Proceedings of the Royal Society. A. Mathematical, Physical and Engineering Sciences

DOI:https://doi.org/10.1098/rspa.1962.0037· OSTI ID:4809653

Patterson, H.; Tomlin, D. H.

By incorporating the radioactive isotope Au/sup 198/ either homogeneously or in specific layers parallel to the surface in plane, polycrystalline gold targets, it was possible to investigate the angular distributions of particles ejected in the sputtering process induced by bombardment with Ar⁺ and Kr⁺ ions in the energy range 5 to 10 kev, and also to study the ejection of particles from different depths below the surface of the target. Compared with a cosine-law representation, the angular distributions were found to be more strongly peaked in the direction of the target normal. This departure from the cosine law was found: to decrease with decreasing ion energy; to be smaller for Kr⁺ ions than for Ar⁺ ions of the same energy; and to decrease when the Au/sup 198/ was restricted to thin surface layers. These results show systematic behavior with respect to the penetration range of the incident ions and are consistent with the view that the sputtering process includes the ejection of atoms from finite depths, resulting in some degree of collimation along the target normal. Direct experimental verification of this conclusion was sought by the use of subsurface layers of Au¹⁹⁸. With Ar/sup +/ ions of 8 kev energy a significantly positive result was obtained, but the depth involved with Kr/sup +/ ions of the same energy was much smaller. The maximum depths from which Au atoms were ejected by Ar⁺ and Kr⁺ ions of this energy were found to correspond reasonably with calculated ion ranges. The experiments showed that in the sputtering process, atoms are ejected.

• Research Organization: Atomic Weapons Research Establishment, Aldermaston, Berks, Eng.; and Univ. of Reading, Eng.
• Sponsoring Organization: USDOE
• NSA Number: NSA-16-010739
• OSTI ID: 4809653
• Journal Information: Proceedings of the Royal Society. A. Mathematical, Physical and Engineering Sciences, Journal Name: Proceedings of the Royal Society. A. Mathematical, Physical and Engineering Sciences Journal Issue: 1323 Vol. 265; ISSN 1364-5021
• Publisher: The Royal Society Publishing
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
ARGON
CRYSTALS
EMISSION
ENERGY
ENERGY RANGE
GOLD
GOLD 198
ION BEAMS
KEV RANGE
KRYPTON
LABELLED COMPOUNDS
MEASURED VALUES
SPUTTERING
SURFACES
TARGETS
THICKNESS
TRACE AMOUNTS