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Proceedings Paper

Comparative study of supertips for electron field emitters
Author(s): Hans W. P. Koops; Mark A. Weber; J. Urban; C. Schoessler
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Paper Abstract

A numerical study of tips and supertips prone for fieldemission sources is performed using a 3D numerical electron optics package. Special supertips are fabricated with additive lithography under computer control. Different materials are used to generate amorphous or nanocrystalline tips. Its performance is simulated. Additive lithography using electron beam induced deposition allows to design base radii from 50 to 1000 nm. Tip radii and tip length of similar dimensions can be generated. Supertips on top of a deposited tip can have a radius as small as 5 nm. This is achieved using a high resolution scanning electron microscope with a cold field emission source. Gold-tips are constructed on top of Pt/Ir-wire tips. The positioning accuracy is 20 nm. Tips are routinely produced with aspect ratios of 5 to 10 and give an additional field enhancement factor. The influence of the nanocrystallinity of the deposited material to the field enhancement is investigated. Nanocrystals at the tip enhance the field up to a factor of 4. This effect explains the high emission current obtained in experiments from nanocrystalline tips.

Paper Details

Date Published: 25 September 1995
PDF: 11 pages
Proc. SPIE 2522, Electron-Beam Sources and Charged-Particle Optics, (25 September 1995); doi: 10.1117/12.221573
Show Author Affiliations
Hans W. P. Koops, Deutsche Telekom AG (Germany)
Mark A. Weber, Deutsche Telekom AG (Germany)
J. Urban, Technische Hochschule Darmstadt (Germany)
C. Schoessler, Technische Hochschule Darmstadt (Germany)

Published in SPIE Proceedings Vol. 2522:
Electron-Beam Sources and Charged-Particle Optics
Eric Munro; Henry P. Freund, Editor(s)

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