Fabrication of planarized small area Nb/Al,AlOx/Al/Nb Josephson tunnel junctions using reactive ion etching in SF6

D.J. Adelerhof, M.E. Bijlsma, P.B.M. Fransen, T. Weiman, J. Flokstra, H. Rogalla

Research output: Contribution to journalArticleAcademicpeer-review

18 Citations (Scopus)
86 Downloads (Pure)


High quality Nb/Al,AlOx/Al/Nb Josephson tunnel junctions have been made with the help of a fabrication process based on reactive ion etching of Nb in SF6. The Vm value of these junctions is typically 60–70 mV at 4.2 K. At 1.6 K, a Vm of 4.1 V has been measured, which is the highest value that has ever been reported for this type of junction. The area of the junctions ranges from 1 to 25 μm2. By burying the Nb/Al,AlOx/Al/Nb trilayer in the substrate, a planarized junction configuration has been obtained. Reactive ion etching of Nb in SF6 plasmas has been studied in detail. Anisotropic etch profiles can be obtained because of the formation of a resistant layer during etching, which prevents etching of Nb under the photoresist. The etching process has been monitored with a spectrometer. The fluorine emission at 703.7 nm is shown to be suitable for end point detection.
Original languageEnglish
Pages (from-to)477-485
Number of pages9
JournalPhysica C
Issue number209
Publication statusPublished - 1993


Dive into the research topics of 'Fabrication of planarized small area Nb/Al,AlO<sub>x</sub>/Al/Nb Josephson tunnel junctions using reactive ion etching in SF<sub>6</sub>'. Together they form a unique fingerprint.

Cite this