Dresden 2014 – scientific programme

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DS: Fachverband Dünne Schichten

DS 17: Ion and Electron Beam Induced Processes

DS 17.6: Talk

Tuesday, April 1, 2014, 15:15–15:30, CHE 91

Novel porous liquid metal ion source for surface modification with heavy polyatomic ions — •Daniel Bock¹, Wolfgang Pilz¹, Martin Tajmar¹, and Lothar Bischoff² — ¹Technische Universität Dresden, 01062 Dresden — ²Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328 Dresden

The most common Liquid Metal Ion Source emitters for focused ion beam (FIB) applications are from the tungsten needle type. Wetted with different elementary or alloy materials, a broad spectrum of mono- and polyatomic ions can be extracted and applied for surface modification purposes by using ion optics containing an ExB mass filter which is not restricted to FIB but to single ended ion accelerators as well. It was recently shown, that the impact of heavy polyatomic ions leads to quite different interactions on material surfaces as it is known up to now due to the enormous local energy deposition [1].

A new Micro-Powder Injection Molding technique allows the fabrication of porous tungsten emitters in nearly any shape, which is not accessible by mechanical machining [2]. Such porous tungsten emitters combine the advantages of needle and capillary type emitters. Due to their improved wettability and material flux, such an emitter can deliver ion currents of tens of µA concentrated in one beam focused by a special ion optics design. This new type of LMIS as well as its fabrication procedure and operational conditions will be discussed using a GaBi alloy liquid metal ion source.

[1] L. Bischoff, et al., Nucl. Instr. and Meth. B 272 (2012) 198.

[2] M. Tajmar, et al., Ultramicroscopy 111(2010)1.