Electron-beam characteristics of double-gated Si field emitter arrays

Double-gated Si field emitter arrays were fabricated in order to generate a focused electron beam and their characteristics were measured. These devices were fabricated by reactive ion etching followed by double successive evaporation of insulating layer and electrode. In the present device, the lower gate was used as an extraction electrode and the upper one was used as an electrostatic focusing lens. The device presented here has a 1.2 mu m lower gate opening and a 2.2 mu m upper gate opening, which are smaller than those reported previously by the authors (2 mu m lower gate openings). Beam characteristics such as emission current, focusing properties, spot size, and stability of the focused beam current are reported. (C) 1996 American Vacuum Society.