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O: Fachverband Oberflächenphysik

O 37: Posters: Plasmonics, Electronic Structure and Spin-Orbit Interaction, Semiconductor and Insulator Surfaces, Nanostructures

O 37.94: Poster

Tuesday, April 1, 2014, 18:30–22:00, P2

Controlled electromigration of copper wires and copper thin films — •Julia Hauser¹, Jakob Schwichtenberg¹, Michael Marz¹, Christoph Sürgers¹, Hilbert v. Löhneysen^1,2, and Regina Hoffmann-Vogel¹ — ¹Karlsruher Institut für Technologie, Physikalisches Institut und DFG-Center for Functional Nanostructures, D-76131 Karlsruhe — ²Karlsruher Institut für Technologie, Institut für Festkörperphysik, D-76021 Karlsruhe

Controlled electromigration (EM), i.e., thinning of a metallic wire by cyclic voltage ramping, offers the possibility to fabricate nanocontacts with gaps of a few nanometers in size [1]. We have investigated controlled EM of freely suspended Cu wires under ambient and UHV conditions. We are able to thin the contact down to a conductance of a few conduction quanta G₀=2e²/h, in some cases even to G₀. The onset of the EM follows multiple constant-power curves, as reported earlier [1,2]. Under ambient conditions, we find a negative curvature of the envelope in the first cycles of the EM process before entering the constant-power envelope, which is not observed in UHV. Additionally, we have performed EM on thin Cu films on SiO₂ substrates under ambient conditions as well, in order to study the effect of the sample geometry on EM. We find that the films show qualitatively the same behavior as the ’ambient’ wires. From the maxima of conduction histograms we infer preferred conduction values, whose number in the range of 0<G 10 G₀ depends on the initial thickness of the film.
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