Nanoscale silicon field emitter arrays with self-aligned extractor and focus gates
Author(s)Rughoobur, Girish; Karaulac, Nedeljko; Jain, Lay; Omotunde, Olutimilehin O; Akinwande, Akintunde I
MetadataShow full item record
Out-of-plane focusing is essential for electron beam collimation in gated field emission sources. The focus electrode redirects electrons emitted by the tip with a wide angle towards the central axis, resulting a small focal spot at the anode. Here, we demonstrate for the first time, very high density (10[superscript 8] emitters/cm[superscript 2]) arrays of double-gated field emission electron sources with self-aligned apertures and integrated nanowire current limiters. Release of the emitters after fabrication required the combination of a highly selective dry-etch and an isotropic wet-etch to avoid the loss of the insulator between the two gates. The aperture diameters are ~360 nm and ~570 nm for the extractor gate and focus gate, respectively. The turn-on voltage was low (15-20) V and anode currents of 400 nA were measured at 25 V. We compared devices with different extractor gate thicknesses resulting from planarization non-uniformity, and demonstrate the influence of the focus gate on anode current. The focal spot size was measured, using a low energy phosphor screen, to be around 700 µm for a 500 µm device when the V[subscript FE/V[subscript GE] ratio was 0.35.
DepartmentMassachusetts Institute of Technology. Microsystems Technology Laboratories
Rughoobur, Girish et al. "Nanoscale silicon field emitter arrays with self-aligned extractor and focus gates." Nanotechnology 31, 33 (May 2020): 335203 © 2020 IOP Publishing Ltd
Author's final manuscript