Coarse guidelines in designing focused ion beam optics

Coarse guidelines for designing a two-lens focused ion beam (FIB) column have been proposed, based on the locus of the characteristic point in the FIB spot versus current (i.e., d--Ip) graph in logarithmic scale. Here, the characteristic point is the intersection of two lines corresponding to d=Gaussian beam spot and d=chromatic aberrations spot in the graph. These guidelines are especially useful for designing the FIB column, which is applied both for the milling using wide range diameter FIBs with high current density and for the scanning ion microscope imaging with high image resolution. copyright 1995 American Vacuum Society