Evaluation of a Neon Focused Field Ion Source: Fabrication and Characteristics
A new type of gaseous field ion source, operated with the inert gas neon, was developed. The source material used was the equiatomic B 2-ordered Ni-Al alloy doped with small amounts of W and C. Small surface protrusions were formed by the field evaporation of the multiphase alloy containing ultrafine spherical precipitates. The emission current-voltage characteristics were recorded as a function of neon gas pressure and source temperature. Total source current densities of up to 6 nA were obtained. A source temperature just above the condensation point of Ne gas was found to generate the highest ion current
A novel approach to gaseous field ion sources for focused ion beam applications
Abstract Experiments have demonstrated that significantly increased angular current densities may be obtained from protrusions formed from ultrafine precipitates compared to the normal field ion specimens. The confinement of the ion-emitting region to the precipitates is an effective method of increasing the angular current density. This type of emitter may be a potential candidate for gaseous focused ion sources.
Current-voltage characteristics of a gas field ion source
Current-voltage characteristics of a gas field ion source (GFIS) have been measured for hydrogen and all rare gases. The parameter set included tip temperature, tip radius and gas temperature and pressure. This investigation has been made to get a complete overview of the field ion currents (FIC) and to estimate the maximum currents in a GFIS, which have been found to a few 100 nA. This estimate allows also a feasibility study of a GFIS, modified by a supertip, a small protuberance on the emitter surface.