Field-directed sputter sharpening for tailored probe materials and atomic-scale lithography

• Published in: Nature communications Vol. 3; no. 1; p. 935
• Main Authors: Schmucker, S.W., Kumar, N., Abelson, J.R., Daly, S.R., Girolami, G.S., Bischof, M.R., Jaeger, D.L., Reidy, R.F., Gorman, B.P., Alexander, J., Ballard, J.B., Randall, J.N., Lyding, J.W.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 03-07-2012; Nature Publishing Group
• Subjects: 639/766/25; 639/766/36; 639/925; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms1907

Fabrication of ultrasharp probes is of interest for many applications, including scanning probe microscopy and electron-stimulated patterning of surfaces. These techniques require reproducible ultrasharp metallic tips, yet the efficient and reproducible fabrication of these consumable items has remained an elusive goal. Here we describe a novel biased-probe field-directed sputter sharpening technique applicable to conductive materials, which produces nanometer and sub-nanometer sharp W, Pt-Ir and W-HfB
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tips able to perform atomic-scale lithography on Si. Compared with traditional probes fabricated by etching or conventional sputter erosion, field-directed sputter sharpened probes have smaller radii and produce lithographic patterns 18–26% sharper with atomic-scale lithographic fidelity.
Scanning probe microscopy and related techniques rely on the availability of very sharp tips. Here, a sharpening technique based on field-directed sputtering is demonstrated, resulting in ultrasharp metallic tips for use in scanning tunnelling microscopy as well as atomic-scale lithographic experiments.