NbN/MgO/NbN edge-geometry tunnel junctions
- 3 July 1989
- journal article
- conference paper
- Published by AIP Publishing in Applied Physics Letters
- Vol. 55 (1) , 81-83
- https://doi.org/10.1063/1.101760
Abstract
We report the fabrication and low‐frequency testing of the first edge‐geometry NbN/MgO/NbN superconducting tunnel junctions. The use of an edge geometry allows very small junction areas to be obtained, while the all‐NbN electrodes permit operation at 8–10 K with a potential maximum operating frequency above 1 THz. Edge definition in the base NbN film was accomplished utilizing Ar ion milling with an Al2O3 milling mask, followed by a lower energy ion cleaning step. This process has produced all‐refractory‐material tunnel junctions with areas as small as 0.1 μm2, resistance‐area products less than 21 Ω μm2, and subgap to normal state resistance ratios larger than 18.Keywords
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