Mass spectra of Au-Si alloy liquid metal ion sources

Abstract

Measurements are reported on the mass spectrum of an Au-Si alloy liquid metal ion source with various alloy compositions and values of total source current. To obtain a high fraction of Si ions, it is best to use an alloy composition with a higher silicon content than that of the eutectic composition. It is shown that the fraction of Si2+ ions is independent of the total source current, whereas the Si+ fraction increases with increasing current. The eutectic composition and the temperature of the solidus line were determined to be (18.0+or-0.5) atomic per cent and (362+or-4) degrees C, respectively.