Direct observation of the thickness distribution of ultra thin AlOx barriers in Al/AlOx/Al Josephson junctions
Journal article, 2015

We have directly measured the thickness distribution of the tunnel barriers in state-of-the-art Al/AlOx/Al tunnel junctions. From the distribution we can conclude that less than 10% of the junction area dominates the electron tunnelling. The barriers have been studied by transmission electron microscopy, specifically using atomic resolution annular dark field (ADF) scanning transmission electron microscopy (STEM) imaging. The direct observation of the local barrier thickness shows a Gaussian distribution of the barrier thickness variation along the junction, from ~1 to ~2nm. We have investigated how the thickness distribution varies with oxygen pressure (Po) and oxidation time (to) and we find, in agreement with resistance measurements, that an increased to has a larger impact on barrier thickness and its uniformity compared to an increased Po.

TEM

Tunnel barriers

Aluminum

Josephson junctions

Author

Lunjie Zeng

Chalmers, Applied Physics, Eva Olsson Group

Samira Mousavi Nik

Chalmers, Applied Physics, Eva Olsson Group

Tine Greibe

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Philip Krantz

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Christopher Wilson

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Per Delsing

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Eva Olsson

Chalmers, Applied Physics, Eva Olsson Group

Journal of Physics D: Applied Physics

0022-3727 (ISSN)

Vol. 48 39 395308- 395308

Areas of Advance

Nanoscience and Nanotechnology

Subject Categories

Nano Technology

Condensed Matter Physics

DOI

10.1088/0022-3727/48/39/395308

More information

Created

10/7/2017