Depth of origin of sputtered atoms: Experimental and theoretical study of Cu/Ru(0001)

Journal Article · Sun May 01 04:00:00 EDT 1988 · J. Vac. Sci. Technol., A; (United States)

DOI:https://doi.org/10.1116/1.575604· OSTI ID:5155409

Burnett, J W; Biersack, J P; Gruen, D M; Joergensen, B; Krauss, A R; Pellin, M J; Schweitzer, E L; Yates, Jr, J T; Young, C E

The depth of origin of sputtered atoms is a subject of considerable interest. The surface sensitivity of analytical techniques such as secondary ion mass spectrometry and surface analysis by resonance ionization of sputtered atoms (SARISA), and the sputtering properties of strongly segregating alloy systems, are critically dependent on the sputtering depth of origin. A significant discrepancy exists between the predictions of existing analytical sputtering theories and computer sputtering models; in general, the computer models predict a much shallower depth of origin. The existing experimental evidence suggests that most of the sputtered atoms originate in the topmost atomic layer, but until recently, the results have not been definitive. We have experimentally determined the depth of origin of atoms sputtered from surfaces consisting of Cu films of <2 monolayers on a Ru(0001) substrate. The Cu/Ru target was statically sputtered using 3.6-keV Ar/sup +/. The sputtered neutrals were nonresonantly laser ionized and detected using SARISA. The Cu/Ru sputtering yield ratio and the suppression of the Ru sputtering yield were determined for various Cu coverages. The results indicate that the majority of the sputtered atoms originate in the topmost atomic layer. The Cu/Ru system is also modeled using a modified transport of ions in matter (t-smcapsr-smcapsIm-smcaps) code. It was found that t-smcapsr-smcapsIm-smcaps -smcapsc-smcaps does not correctly treat the first atomic layer, resulting in a serious underestimate of the number of sputtered atoms which originate in this layer. The corrected version adequately describes the results, predicting that for the experimental conditions roughly two-thirds of the sputtered atoms originate in the first atomic layer.

• Research Organization: Pittsburgh Surface Science Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
• OSTI ID: 5155409
• Journal Information: J. Vac. Sci. Technol., A; (United States), Journal Name: J. Vac. Sci. Technol., A; (United States) Vol. 6:3; ISSN JVTAD
• Country of Publication: United States
• Language: English

Related Subjects

656003* -- Condensed Matter Physics-- Interactions between Beams &amp; Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ARGON IONS
CHARGED PARTICLES
COMPUTERIZED SIMULATION
COPPER
ELEMENTS
ENERGY RANGE
IONIZATION
IONS
KEV RANGE
KEV RANGE 01-10
MASS SPECTROSCOPY
METALS
PLATINUM METALS
RUTHENIUM
SIMULATION
SPECTROSCOPY
SPUTTERING
TRANSITION ELEMENTS