B, As and Si Field Ion Sources

Abstract

B, As and Si field ion sources using metal alloys have been built and voltage vs. current characteristics, energy distribution, angular ion current intensity, and mass spectra have been measured. For 11B+ and Si+ ions, an angular ion current intensity of more than 30 µA/sr for 11B+ and 11 µA/sr for Si+ was obtained at an energy spread of 20 eV (FWHM), and for As+ ions, the angular ion current intensity was ∼0.3 µA/sr. By optimising alloy composition, a higher current intensity may be possible. The observed results clearly indicate that use of a metal alloy can extend the applicability of a field ion source over various important elements.