Microguns with 100-V electron beams

The microgun is a combination of a nanotip and a microlens which is composed of two planar micron-size bore electrodes and a coplanar four-pole deflector microfabricated on the same Si chip. The focusing and deflection characteristics of the microgun, working as an immersion lens at 100 V, have been studied both experimentally and by numerical simulations. Results show unique electron optics properties due mainly to the coherence of the electron beam emitted from the nanotip and to the noninteraction of the incident electrons with the different microelectrodes. The focus spot can reach nanometric dimensions with minimum aberrations and a deflection amplitude of ∼2.5 mrad/V.