Field Ion Sources Using Eutectic Alloys

Field ion sources using Si-Au and Ge-Au eutectic alloys have been built and their operating characteristics such as the voltage vs. current characteristic, energy and angular distributions have been measured. An angular current density larger than 1.0×10-3 A/sr was obtained both for Si-Au and Ge-Au field ion sources. The width of the energy distribution curves varied with the square root of the ion current which suggests broadening by a space charge effect. The observed results indicate that eutectic alloys can extend the applicability of a field ion source over various elements.