Limit resolution in low-voltage FIB without correction of chromatic aberration

The resolution in a scanning focused-ion beam (FIB) microscope is determined by two factors: the size of the ion source image on the target and the particle dispersion in the target. A model of low-voltage micro FIB is proposed and calculated, in which the influence of these factors is reduced. It is shown that a resolution of 1.7 nm can be obtained in the analytical mode under target irradiation by helium ions, with detection of potential-emission secondary electrons, and a resolution of 1.3 nm is possible in the technological mode upon reactive etching of a diamond target by molecular oxygen ions.