A high‐intensity scanning ion probe with submicrometer spot size

A liquid‐metal gallium‐ion source was imaged by unity‐magnification single‐gap accelerating lens with a postlens deflector to form a focused scanning probe. We report the dependence of the probe diameter and probe current on the lens acceptance half‐angle. The results range between probe diameters of 1000 and 5000 A at currents of 0.12–3.0 nA for half‐angles of 1.2–6 mrad. The current density and brightness at the target for the 1000‐A‐diam 57‐kV probe were 1.5 A/cm2 and 3.3×106 A/cm2 sr, respectively. Astigmatic probes were also produced with dimensions smaller than 1000 A.