FABRICATION OF SILICON FIELD EMITTER ARRAYS INTEGRATED WITH BEAM FOCUSING LENS

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 arran ged in the same way as a confocal in-plane lens structure. The inner g ate acts as an extraction gate with a 0.6-mu m-diameter opening and th e outer one acts as an electrostatic focusing lens with a 2.4-mu m-dia meter opening. The field emission characteristics were evaluated and a beam current of 70 nA/tip was obtained when a bias voltage of 70 V wa s applied to the two gates. The beam focusing characteristics were als o evaluated and the beam could be focused by decreasing the focusing l ens voltage without a significant decrease in the beam current.