Fabrication of Silicon Field Emitter Arrays Integrated with Beam Focusing Lens

Abstract

A new field emitter structure capable of generating a focused electron beam (FEB) was fabricated. The present structure is basically similar to a double-gated structure, however, the two gate openings are arranged in the same way as a confocal in-plane lens structure. The inner gate acts as an extraction gate with a 0.6-µm-diameter opening and the outer one acts as an electrostatic focusing lens with a 2.4-µm-diameter opening. The field emission characteristics were evaluated and a beam current of 70 nA/tip was obtained when a bias voltage of 70 V was applied to the two gates. The beam focusing characteristics were also evaluated and the beam could be focused by decreasing the focusing lens voltage without a significant decrease in the beam current.