- You are here: Home > ST323 - Fabrication of Nb/Al2O3/Nb Josephson Junctions Using in situ Magnetron Sputtering and Atomic Layer Deposition
You are here
ST323 - Fabrication of Nb/Al2O3/Nb Josephson Junctions Using in situ Magnetron Sputtering and Atomic Layer Deposition
Fabrication of Nb/Al2O3/Nb Josephson Junctions Using in situ
Magnetron Sputtering and Atomic Layer Deposition
Rongtao Lu, Alan J. Elliot, Logan Wille, Bo Mao, Siyuan Han,
Judy Z. Wu, John Talvacchio, Heidi M. Schulze, Rupert M. Lewis,
Daniel J. Ewing, H. F. Yu, G. M. Xue, and S. P. Zhao
Abstract - Atomic layer deposition (ALD) provides a promising approach for deposition of ultrathin low-defect-density tunnel barriers, and it has been implemented in a high-vacuum magnetron sputtering system for in situ deposition of ALD-Al2O3 tunnel barriers in superconductor-insulator-superconductor (SIS) Josephson junctions. A smooth ALD-Al2O3 barrier layer was grown on a Al-wetted Nb bottom electrode and was followed with a top Nb electrode growth using sputtering. The formation of tunnel barriers in these Nb/ALD-Al2O3/Nb trilayers was strongly indicated at room temperature by using the current-in-plane tunneling technique. Preliminary low temperature measurements of current-voltage characteristics (IVC) of the Josephson junctions made from these trilayers confirmed the integrity of the ALD-Al2O3 barrier layer. However, the IcRN product of the junctions is much smaller than the value expected from the Ambegaokar-Baratoff formula suggesting a significant pair-breaking mechanism at the interfaces.
Keywords - Atomic layer deposition, Josephson junction.
IEEE/CSC & ESAS European Superconductivity News Forum (ESNF) No. 22 October/November 2012. ESNF Reference No.ST323 Category 6.
The published version of this preprint appeared in IEEE Transactions on Applied Superconductivity 23, 1100705 (June 2013).