New thickness control process of oxide barrier for Nb-based tunnel junctions

New thickness control process of oxide barrier for Nb-based tunnel junctions

The Nb-based superconductor-insulator-superconductor (SIS) tunnel junctions have been broadly used in many applications. The critical current density (J/sub C/), one of the most important parameters of SIS tunnel junction, is usually controlled by the oxygen exposure (E/sub O2/) of the Al oxidation...

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Bibliographic Details
Published in:IEEE transactions on applied superconductivity Vol. 13; no. 2; pp. 1100 - 1103
Main Authors: Ming-Jye Wang, Hong-Wen Cheng, Sing-Lin Wu, Pi-Kuang Chuan, Chi, C.C.
Format: Journal Article Conference Proceeding
Language:English
Published: New York, NY IEEE 01-06-2003
Institute of Electrical and Electronics Engineers
The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subjects:
Applied sciences
Critical current density
Degradation
Electrical engineering. Electrical power engineering
Electrical machines
Electronics
Exact sciences and technology
Fabrication
Gold
Insulators
Josephson junctions
Materials
Niobium
Oxidation
Physics
Q factor
Regulation and control
Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
Superconducting devices
Thickness control
Various equipment and components
Critical current density
Insulator
Q factor
Dielectric materials
Process control
Blocking layer
oxygen exposure
Composite material
Thickness
Josephson tunnel junction
Superconducting materials
SIS junctions
Deposit formation
AuAl2
Tunnel junction
Oxidation
Thickness control
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Summary:The Nb-based superconductor-insulator-superconductor (SIS) tunnel junctions have been broadly used in many applications. The critical current density (J/sub C/), one of the most important parameters of SIS tunnel junction, is usually controlled by the oxygen exposure (E/sub O2/) of the Al oxidation process. R. E. Miller et al. demonstrated the relation between J/sub C/ and oxygen exposure using the SNEP process. However, the value of J/sub C/ still varies with Nb/AlO/sub x/Al/Nb deposition system, even run-to-run process. A new AuAl/sub 2//Al composite, instead of pure Al, has been used in the oxidation process. From the J/sub C/-E/sub O2/ relation, we have demonstrated the oxidation rate of AuAl/sub 2/ is about 400 times lower than that of Al. Using AuAl/sub 2/ layer, two advantages are observed. 1) For low J/sub C/ tunnel junctions, the thickness of AlO/sub X/, or J/sub C/, can be controlled easily by inserting AuAl/sub 2/ layer as a blocking layer in oxidation process. 2) High quality factor tunnel junctions with J/sub C/>100 kA/cm/sup 2/ are achieved by oxidation of AuAl/sub 2/ layer directly.
Bibliography:ObjectType-Article-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
content type line 23
ISSN:1051-8223
1558-2515
DOI:10.1109/TASC.2003.814165