Angular distributions of sputtered particles from lithium-implanted aluminium and copper crystals

The anisotropy of angular distributions of sputtered ions from lithium-implanted aluminium and copper single crystals, measured by SIMS analysis, have been used to obtain information about the microstructure of the implanted layers. Sputtered Al + distributions from the {111} surface show three-fold symmetry with maximum intensity near the 〈110〉 and 〈100〉 directions respectively, while Li + distributions show maximum intensity only in the 〈100〉 directions. From {100] crystals the Al + distributions have four-fold symmetry while there are no preferential ejection directions for the Li + ions. This agrees conceptually with the fact that the implanted layer contains the ordered Al 3Li (δ') phase, which has earlier been observed by TEM analysis on implanted samples. In contrast, a similar study of Li + implanted copper crystals shows that the implanted lithium is randomly located.