Reduced Sputtering Yields for Two-Phase Ag–Ni and Ag–Co Targets

Abstract

Sputtering yields of water-cooled two-phase Ag–Ni and Ag–Co targets were found to be much lower than predicted by averaging the yields of the unalloyed metals. The target yields steadily decreased when the Ni or Co content increased from 0 to 30 at. %. Above 30-at. % Ni or Co, the yields did not change and were equal to the respective yields for Ni and Co. Thus, the results indicate that yields may be predictable for some multiphase targets from the yield of the low-yield phase. The unusually low yields were attributed to coating of the high-yield Ag phase with lower-yield Ni or Co during sputtering. Simultaneous coating and sputtering processes reached steady state before removal of 20 μ from freshly prepared non-presputtered Ag–Ni targets even though Ni particles were up to 130 μ in diameter. Quantitative microprobe analysis of one Ag–Ni deposit indicated deposit compositions were nearly the same as target compositions.