Photolithographic fabrication of lead alloy Josephson junctions
Techniques for the photolithographic fabrication of thin-film Josephson junctions are presented in detail, including metal liftoff processes, lead alloy composition, and formation of tunneling junction barriers using plasma oxidation in an rf discharge. A comparison with earlier rf plasma oxidation studies on Pb(In) --oxide--Pb junctions shows the tunneling resistance of Pb(In,Au) --oxide--Pb(Au) junctions to be nearly two decades lower for a given oxygen pressure in the rf discharge; this difference was attributed to the use of different alloys and sputtering parameter measurement techniques in the respective studies. Typically, tunneling resistance decreased by only 2% after ten thermal cycles, but decreased at an accelerated rate with subsequent cycling. Room-temperature storage often induced downward resistance changes on the order of 30% per month. Junctions stored at -15/sup 0/C generally showed little change after a period of three months.
- Research Organization:
- National Bureau of Standards, Boulder, Colorado 80302
- OSTI ID:
- 6804623
- Journal Information:
- J. Vac. Sci. Technol.; (United States), Journal Name: J. Vac. Sci. Technol.; (United States) Vol. 15:2; ISSN JVSTA
- Country of Publication:
- United States
- Language:
- English
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