J. Phys. Colloques
Volume 50, Numéro C8, Novembre 198936th International Field Emission Symposium
|Page(s)||C8-165 - C8-169|
J. Phys. Colloques 50 (1989) C8-165-C8-169
EMISSION CHARACTERISTICS OF LIQUID METAL ION SOURCEH. ARIMOTO1 et M. KOMURO2
1 Fujitsu Laboratories Ltd., 10-1 Morinosato-Wakamiya, Atsugi 243-01, Japan
2 Electrotechnical Laboratory, 1-1-4 Umezono, Tsukuba 305, Japan
Energy distributions of Au-Si-Be, Au-Si, Pd-Ni-Si-Be-B, and Pt-Si liquid metal alloy ion sources were investigated, being focused on behaviors of Si++ and Si+. We found that the energy spreads of the Si++ and Si+ were kept constant at 6 to 7.5 eV, even at an extremely low emission current (50 nA). This saturation results in a decrease in the figure of merit, (dI/dΩ)/ (ƊE)2, for an ion probe forming. (dI/dΩ : angular current density, ƊE : energy spread) The energy distribution profiles suggest plural ion formation mechanisms such as field evaporation, free space field ionization, and charge transfer collision for singly charged ions. We first observed subsidiary shoulders in the Si++ energy distribution curves which cause an expansion of energy spread. This suggests two mechanisms for the Si++ ion formation such as field evaporation and postionization to doubly charged state.