Cryogenic characterization of Josephson junctions

Cryogenic characterization is a crucial part of understanding the behavior of low-temperature quantum electronics. Reliable device testing provides the feedback to fabrication process development, facilitating the rapid development of quantum devices. The research presented in this thesis explores the cryogenic testing, analysis, and characterization of a superconducting quantum device, the Josephson junction. This thesis begins with a theoretical description of superconductivity and Josephson junctions, two superconductors separated by a thin insulating battier. Two models of Josephson barriers are presented for use in analysis. The effect of self-induced magnetic field is considered. A numerical simulation is performed to justify neglecting effects of self-induced magnetic field in junctions of diameter less than the Josephson penetration depth Aj. Lincoln Laboratory's Josephson junction fabrication effort is described along with the apparatus used to test junctions at 4.2 K. Custom software used to test these junctions is then presented. The analysis of 4.2 K data is shown with a simple model of a disc as the insulating barrier. 391 valid Josephson junctions are analyzed across 16 wafers in 3 runs.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Brown, Keith Andrew

Advisor dc:contributor.advisor

• Leonid Levitov and William D. Oliver.

• Physics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/36132

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/36132