Fabrication of miniaturized Schottky emitter by wire electrical discharge machining (WEDM)

The Schottky emitter is extensively used in scanning electron beam lithography machines because of its high brightness and stable current. For its use in parallel electron beam lithography to increase the throughput, we are investigating the possibility of creating an array of miniaturized Schottky emitters. This paper discusses a novel method of fabricating a miniaturized Schottky emitter of 1 mm diameter by wire-electro discharge machining (WEDM). Various WEDM process parameters were optimized for better reproducibility and surface finish of the fabricated emitter. The fabricated samples match well with the intended input design, with no visible stress or bending. Joule heating in vacuum shows good operational feasibility and temperature stability. After heating, the tip becomes as sharp as conventional Schottky emitters. The miniaturized emitter operates at a relatively low power.