Microelectronic Engineering 61–62 (2002) 665–670 www.elsevier.com / locate / mee Fabrication of carbon nanotips in a scanning electron microscope for use as electron field emission sources a, a b b a * S.D. Johnson , D.G. Hasko , K.B.K. Teo , W.I. Milne , H. Ahmed a MRC, Cavendish Laboratory, University of Cambridge, Cambridge CB30HE, UK b Engineering Department, University of Cambridge, Trumpington Street, Cambridge CB21 PZ, UK Abstract Results are reported on the fabrication of carbon nanotips by means of carbon contamination in a conventional SEM system. The carbon nanotips are conical with an apex radius of typically 30 nm, which is subsequently reduced to under 10 nm using an oxygen plasma etch. The resulting carbon nanotip is amorphous in structure with a conductivity of 1.1V cm. Preliminary field emission results using a carbon nanotip mounted on a fused tungsten needle are also presented.  2002 Elsevier Science B.V. All rights reserved. Keywords: Carbon contamination; Field emission; Nanotip 1. Introduction The fabrication of cold cathodes for use in vacuum microelectronic devices [1,2] has been the focus of much research due to their unique properties: ballistic electron transport, high current densities, and operating characteristics effectively independent of radiation and temperature. These result in a wide range of potential applications including high frequency devices, sensors, and high brightness electron sources for electron-beam applications. Nano-scale field emission devices, or nanotips, show emission characteristics associated with their atomic size: self-collimation of the angular beam spread, a narrow energy spread indicating electron emission from a localized band structure and high stability. Electron beams from such nanotips are coherent and have thus been used in electron interferometry and holography. Although understanding of the characteristics of these nanotips is increasing, the fabrication procedures still require further development before nanotips and their related devices become a reliable and practical technology. This paper presents a simple technique for the fabrication of such nanotips using carbon contamination in conventional scanning electron microscopy (SEM). *Corresponding author. E-mail address: sdj24@cam.ac.uk (S.D. Johnson). 0167-9317 / 02 / $ – see front matter  2002 Elsevier Science B.V. All rights reserved. PII: S0167-9317(02)00431-8