Uniform High-Current Cathodes Using Massive Arrays of Si Field Emitters Individually Controlled by Vertical Si Ungated FETs—Part 2: Device Fabrication and Characterization

We report the demonstration of electron sources that achieve high-current and uniform emission using dense arrays of Si field emitters (FEs) that are individually ballasted by a current source. Each FE is fabricated on top of a vertical ungated field-effect transistor (FET), a two-terminal device based on a very-high-aspect-ratio Si column. The ungated FET takes advantage of the velocity saturation of electrons in silicon, the high aspect ratio of the ungated FET, and the doping concentration to achieve current-source-like behavior to obtain reliable uniform and high-current electron emission. Emitted currents in excess of 0.48 A were demonstrated.