FABRICATION OF LATERAL-TYPE THIN-FILM EDGE FIELD EMITTERS BY FOCUSED ION-BEAM TECHNIQUE

Lateral-type, thin-film, edge field emitters have been fabricated with a focused ion beam (FIB) technique. A metal thin film deposited on the thermally oxidized silicon wafer was cut by a 20 keV gallium ion beam with a diameter of 1-2 μm to produce an emitter-collector gap. One of the advantages of the present procedure is such that the edge of the emitter could be sharpened owing to the current density distribution of the FIB. Another advantage is precise controllability of the emitter-gate gap. Nickel, chromium, and platinum emitters were fabricated. It was found that the chromium emitters exhibited superior properties as compared with the other materials. Electron emission characteristics were also investigated for the single emitters and for the arrayed emitters made of chromium. By adding an external collector, the device showed triode characteristics.