Construction of STM aligned electron field emission source

We constructed a scanning tunneling microscope aligned field emission (SAFE) source by using silicon micro-fabricated electrostatic lenses. The system consists of an STM aligned field emitter, 5 mu m extractor, 100 mu m accelerator, beam dump, quadrupole deflector and einzel lens. The microlenses were made by using silicon processing techniques. The system can be operated from 200 to 2 kV, resulting in a beam current of tens of nA and with the diameter of similar to 0.1 mu m when a sample was placed less than 2 mm away from the exiting einzel lens. In order to measure the spherical and chromatic aberrations, a detector and cylindrical electron energy analyzer were attached to the micro-column.