Fabrication and characterization of bulk molybdenum field emission arrays

Abstract

This paper reports a simple technology for fabricating high aspect ratio (>10) field emission tips directly in molybdenum substrate by fluorine inductive-coupled-plasma (ICP) etching for the first time. Compared to the traditional Spindt array, the film interface is eliminated, and the device exhibits a low turn-on electric field of 1.21V/μm. Arrays of 1,000,000 tips with 10μm pitch are employed to emit currents of 140μA at electric field strength of 5.48V/μm. A stable, uniform emission was observed in a field emission display. With better conductivity and thermal conductivity, the Mo-FEAs are very promising for long-term and continuous emission.

Bulk molybdenum field emitters by inductively coupled plasma etching

“…The fabrication process is reported in detailed elsewhere. 10,11 For brevity, and as shown in Fig. 1(a), a double-side-polished, 400 mm thick, 4-inch high purity (99.95%) Mo wafer was first coated with an evaporated 500 nm thick Al film to form an etch hard mask.…”

“…Molding, [1][2][3] through-aperture evaporation, [4][5][6][7][8][9] dry etching, [10][11][12][13][14][15] hot-embossing, 16 stamping, 17 and wet etching 18,19 have all been proposed as means of fabricating Spindt-type field emission arrays (FEA). In the case of molding techniques, [1][2][3] tips are formed by the deposition of the emitter material on mask protrusions.…”

A Graphene-Coated Mo Tip Array for Highly-Efficient Nanostructured Electron Field Emitters

“…The emission current is highly dependent on both the geometry of the cathode and the material properties. Based on this, at specific fields, lowering the work function of the materials with high aspect ratio emitters is capable of producing higher emission currents [ 31 , 32 ].…”

Design, Fabrication and Characterization of Molybdenum Field Emitter Arrays (Mo-FEAs)

“…Research on field emitter arrays (FEAs) has been actively pursued with the aim of realizing high current and high current density cathodes, especially for the applications in vacuum electronics [ 1 ], display technology [ 2 ], and medical X-ray imaging [ 3 ]. However, field emission sources are yet to be adopted in demanding applications because of emitter tip radius variation across an array, which results in spatial and temporal variations of emission current [ 4 ]. To address the issues of reliability and uniformity, various approaches have been developed over the past few decades to outperform competing cathode designs.…”