Toward Amp-Level Field Emission With Large-Area Arrays of Pt-Coated Self-Aligned Gated Nanoscale Tips

Abstract

Design, fabrication, and characterization of Pt-coated, self-aligned, and gated Si field emission arrays are reported. Arrays of 320 000 tips with 10 µm pitch are employed to emit currents as high as 0.35 A (current density of 1.1 A/cm 2 ) at gate-emitter biases of 300 V. For reliability, the devices have a gate dielectric thicker than 2.5 µm maintaining the field inside gate insulator below 150 V/µm and a 5-nm-thick Pt-coating protecting the tips against sputtering by back-streaming ions. The Pt-coating also increases the capture cross section of electrons from the emitter cone, resulting in higher emission currents compared with uncoated Si tips when the supply of electrons is limited to the surface. The device failure at high currents is associated with plasma ignition due to local pressure rise caused by outgassing of the anode. At lower emission currents, the devices are capable of long-term emission (>3 h) at pressures as high as 10 −5 Torr. Furthermore, a high-yield fabrication process is presented for large-area fabrication of highly-uniform gated tip arrays that could be expanded to active areas larger than 10 cm 2 to increase the emission current.

High‐Performance On‐Chip Thermionic Electron Micro‐Emitter Arrays Based on Super‐Aligned Carbon Nanotube Films

“…It can be seen from the I collect − V driven curve that, I collect becomes measurable when the V driven is larger than ≈3.1 V. It then increases exponentially with V driven and approaches ≈20 µA at V driven = 3.9 V. Taking the horizontally projected area of emitting SACNT films (S = 1500 µm 2 ) into consideration, an emission current density up to ≈1.33 A cm −2 is obtained, which is comparable to that of commercial thermionic electron emitters. [19,20] The driven voltage as a function of emission current density from the device measured in Figure 2b together with those of previously reported gated FEAs [21][22][23][24][25][26] are plotted on the same graph in Figure 2c. Here, driven voltage of FEAs refers to the voltage applied to the gate electrode.…”

Electron Emission Devices for Energy‐Efficient Systems

“…The Ohmic contact and the two‐stage field enhancement together increase the overall field emission performance. A few more recent studies in this domain are cited here and some significant studies are listed in Table .…”

“…FED requires large‐area field emission sources. In that context, extensive research is ongoing for field emission arrays (FEAs) and gated‐field emission arrays to modulate the emission current. Few latest significant studies are silicon‐based FEA, diamond‐based FEA, ZnO‐based FEA, and CNT‐based FEA …”

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

“…According to the widely adopted field emission theory for bulk metallic emitters, the emission current can be calculated by the tunneling probability across the potential barrier and the supply rate of electrons to the surface [ 23 ]. Based on the Fowler–Nordheim (F–N) equation [ 24 ], the emission current density J (A/cm 2 ) can be expressed as where is the electric field at the tip apex, is the emitter surface work function, and ; . is the slope correction factor.…”