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.

The “LED‐version” of the electron gun

“…Most fabrication methods in the literature rely on lithography in a clean room. In the following a method using only a wafer dicing saw and a wet chemical etch is presented [19]. Fig.…”

“…For a detailled and reproducible investigation the current needs to be controlled and constant over a longer period of time. Prommesberger et al [21] proposed a control circuit whose functionality was shown multiple times in previous lifetime measurements on silicon based FEAs [19,22]. A schematic of the transistor based regulation circuit is depicted in Fig.…”

Quantitative Field Emission Imaging for Studying the Doping-Dependent Emission Behavior of Silicon Field Emitter Arrays

“…The investigated FEAs were fabricated by wafer dicing and wet chemical TMAH etching [37] of n (phosphorus, resistivity of 10-20 Ωcm), n ++ (antimony, resistivity of <0.005 Ωcm) and p (boron, resistivity of 10-20 Ωcm) doped Si <100> substrates. Fabrication parameters were adjusted to produce morphologically comparable arrays of 30 × 30 pyramidal-shaped tips for each doping with an average height of approximately 30 µm and a pitch of 66.7 µm.…”

“…The FEA is pulled to a negative potential by a regulation circuit [36,39] The measurements are performed in a vacuum setup with a controlle pressure of 10 −5 mbar. This relatively high pressure for field emission measur chosen to investigate the emission behavior of the FEAs under real application [37]. The main component of the measurement setup is the Raspberry Pi H (Raspberry Pi Ltd., Cambridge, UK), which is equipped with the IMX illuminated CMOS imaging sensor [38] with 4056 × 3040 pixels and a pixel 1.55 µm.…”