Silicon field emitters fabricated by dicing-saw and wet-chemical-etching

Abstract

Silicon field emitter arrays (FEAs) with different tip sizes and quantities were fabricated by saw dicing and anisotropic wet chemical etching by tetramethylammonium hydroxide. The tip is formed by the different etching rates of the crystal facets leading to a sharp pyramid based on {103} planes on the top and a hexadecagon based on {331} and {221} planes on the bottom. Electrical measurements at 10−5 mbar up to 10 μA show good reproducibility for FEAs with the same process parameters and higher uniformity and stability with an increasing number of tips. Constant current measurements at the same conditions and 10 μA show a mean electric field increase of about 0.06(3) V/(μm h) for p-type FEAs with a tip quantity of 3600. The shift increases with lower tip quantity and is higher for n-type FEAs compared to p-type. The degradation during the constant current measurement of n-type samples is found to be partly reversible by heating to 200 °C during emission. In contrast, heating of p-type FEAs induced further degradation instead of a regeneration effect.