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arXiv · 1409.7689

The role of titanium in electromigrated tunnel junctions

Martin Frimmer·Gabriel Puebla-Hellmann·Andreas Wallraff·Lukas Novotny
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Abstract

A standard route for fabrication of nanoscopic tunnel junctions is via electromigration of lithographically prepared gold nanowires. In the lithography process, a thin adhesion layer, typically titanium, is used to promote the adhesion of the gold nanowires to the substrate. Here, we demonstrate that such an adhesion layer plays a vital role in the electrical transport behavior of electromigrated tunnel junctions. We show that junctions fabricated from gold deposited on top of a titanium adhesion layer are electrically stable at ambient conditions, in contrast to gold junctions without a titanium adhesion layer. We furthermore find that electromigrated junctions fabricated from pure titanium are electrically exceptionally stable. Based on our transport data, we provide evidence that the barrier in gold-on-titanium tunnel devices is formed by the native oxide of titanium.

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Martin Frimmer, Gabriel Puebla-Hellmann, Andreas Wallraff, Lukas Novotny. 2014-09-26. The role of titanium in electromigrated tunnel junctions. https://doi.org/10.1063/1.4903748

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