Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published January 2, 1983 | public
Journal Article

Sputtering of the gallium-indium eutectic alloy in the liquid phase

Abstract

A central assumption of a recent theory explaining isotopic and chemical fractionation during sputtering is that the sputtered atoms come predominantly from the top monolayer. We first describe ion scattering and Auger spectroscopy results that show, in agreement with rough theoretical expectations, that the surface monolayer of a gallium-indium alloy containing 16.5% indium in bulk is greater than 94% indium, while the next layer can be only slightly enriched. We then report measured sputtering yields and angular distributions of sputtered atoms from both the solid and liquid phases of gallium, indium, and gallium-indium eutectic alloy. These were obtained by Rutherford backscattering analysis of graphite collector foils. The sputtering of the liquid eutectic alloy by 15 keV Ar^+ results in a ratio of indium to gallium sputtering yields which is 28 times greater than would be expected from the target stoichiometry. Furthermore, the angular distribution of gallium is much more sharply peaked about the normal to the target surface than the indium distribution. When the incident Ar^+ energy is increased to 25 keV, the gallium distribution broadens to the same shape as the indium distribution. With the exception of the sharp gallium distribution taken from the liquid eutectic at 15 keV, all angular distribution from liquid targets fit a cos^2θ function. The sputtering yields from the eutectic allow us to infer that 85% of the sputtered atoms originate in the surface monolayer at 15 keV incident energy, while 70% do so at 25 keV.

Additional Information

© 1983 North-Holland. Received 15 June 1982; Accepted for publication 2 November 1982. The work at Caltech was partially supported by the National Science Foundation (CHE81-13272 and PHY79-23638) and the National Aeronautics and Space Administration (NAGW-202 and NAGW-148). The work at Rockwell was supported by NASA Contract NAS9-11539. The work at Yale was supported by USDOE Contract DE-AC02-76ER03074. The able help of Dr. Yuanxun Qiu with the experiments is appreciated.

Additional details

Created:
August 19, 2023
Modified:
October 17, 2023