Effects of a Guardring upon Low-Energy Sputtering Yields of Flat, Single-Crystal Gold Targets

Publisher Website
Google Scholar
Abstract
Spectrometric sputtering yield measurements were performed upon flat, single-crystal gold targets in a supported argon plasma, and the results are compared with those obtained when a large copper guardring was placed about the target. After the results are adjusted to similar discharge conditions, the relative yields without the guardring are greater for all three orientations, (100), (110), and (111). The increase is attributed to the formation of a curvature to the Langmuir layer immediately about the gold target when the guardring is not used. This introduces ions which strike the gold surface at oblique incidence angles. The square root of the relative yield is plotted against the target voltage, and the curves are found to be linear in the range of 40–70 V. The intercepts EE of the extrapolated linear portions of the two curves, with and without a guardring, are found to be equal for each orientation. These values, at 9 μ of argon, are 33, 28.5, and 35 eV for the (100), (110), and (111) faces, respectively. These values do not include the subtractive correction for the plasma potential whose measured value is approximately 15 eV. For the (100) and (111) faces, the calculated differences [EE−EE(110)] are proportional to the corresponding differences in the binding energies of a surface atom which is in an upper, complete lattice plane.

This publication has 13 references indexed in Scilit: