LIQUID ALLOY ION SOURCES FOR PD AND CU

For generation of Cu and Pd ions in liquid metal ion sources Cu-Ga, Cu -Ge, Pd-Ge, Pd-Si and Pd-Sn alloys have been tested as source feed mat erials. The range of coexistence of solid and liquid phases and the eu tectic temperature of the investigated alloys were determined by diffe rential thermal analysis. A stable operation of liquid metal ion sourc es could be obtained with Cu63.5Ge36.5 (at.%) and Pd36Ge64 (at.%) allo ys. The recorded mass spectrum of a Cu63.5Ge36.5 liquid metal ion sour ce has shown a high current of Cu+ ions. The high current of Pd+ ions in the mass spectrum of the Pd36Ge64 liquid metal ion source shows tha t this alloy is a suitable source material for Pd ion generation. An i nvestigation of the ion flux ratio, which depends on the total source current, has revealed a maximum intensity of doubly charged ions in th e low-current region. The fraction of doubly charged Cu and Pd ions is less than 1%.