Fabrication of tungsten-coated silicon-based gated emitters

The present work reports-on the fabrication of tungsten-coated silicon-base d gated emitters. The main fabrication procedures include: forming silicon tips by way of reactive ion etching without thermal oxidation sharpening, t ungsten coating and dielectric layer coating though plasma-enhanced chemica l vapor deposition, metal layer coating by evaporation, and gate aperture o pening by wet chemical etching processes. Scanning electron microscopy in c ombination with energy dispersive x-ray analysis were employed to study the emitters during the fabrication. The radii of the tungsten-coated tips wer e about 30 nm. The gated emitters have a volcano shape with gate aperture d iameter of less than 3 mu m and a silicon dioxide insulating layer 1 mu m t hick. The gated field emitters exhibited a low turn-on voltage of about 60 V. Emission current above 15 mu A from a single emitter was observed. Fowle r-Nordheim plots of the emitted current from these emitters confirmed the f ield emission-behavior. (C) 1999 American Vacuum Society. [S0734-211X(99)09 702-4].