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Published June 2001 | public
Journal Article

Depth of origin of atoms sputtered from crystalline targets

Abstract

Recently, V.I. Shulga and W. Eckstein (Nucl. Instr. and Meth. B 145 (1998) 492) investigated the depth of origin of atoms sputtered from random elemental targets using the Monte Carlo code TRIM.SP and the lattice code OKSANA. They found that the mean depth of origin is proportional to N^(−0.86), where N is the atomic density; and that the most probable escape depth is ∼λ_0/2, where λ_0 is the mean atomic distance. Since earlier molecular dynamics simulations with small crystalline elemental targets typically produced a most probable escape depth of zero (i.e., most sputtered atoms came from the topmost layer of the target), we have carried out new molecular dynamics simulations of sputtered atom escape depths with much larger crystalline targets. Our new results, which include the bcc targets Cs, Rb and W, as well as the fcc targets Cu and Au predict that the majority of sputtered atoms come from the first atomic layer for the bcc(1 0 0), bcc(1 1 1), fcc(1 0 0) and fcc(1 1 1) targets studied. For the high-atomic density targets Cu, Au and W, the mean depth of origin of sputtered atoms typically is less than 0.25λ_0. For the low-atomic density targets Cs and Rb, the mean depth of origin of sputtered atoms is considerably larger, and depends strongly on the crystal orientation. We show that the discrepancy between the single-crystal and amorphous target depth of origin values can be resolved by applying a simple correction to the single-crystal results.

Additional Information

© 2001 Elsevier Science B.V. Supported in part by the National Science Foundation (grants DMR-9712538 at Cal State Fullerton and DMR-9730893 at Caltech). Parts of this work were submitted by E. Trovato as senior thesis in physics at San Diego State University.

Additional details

Created:
August 21, 2023
Modified:
October 17, 2023