Fabrication of Nb-SIS mixers with UHV evaporated Al striplines

J. R. Gao, Sergey Kovtonyuk, J. B. M. Jegers, Pieter Dieleman, T. M. Klapwijk, Herman van de Stadt

Published Mar 1, 1996• 2 citations

Abstract

We have succeeded in developing a novel fabrication process for Nb SIS junctions integrated with an aluminium (Al) stripline for 1 THz waveguide mixers. In particular, a pure Al film, which is evaporated in an ultra-high vacuum system, is applied for the stripline. It can provide a lower surface resistance in comparison with a sputtered Al film, consequently reducing radio frequency (RF) loss in the tuning element. The junctions are fabricated with standard photolithography and typical junction areas are 1 f4m 2 . The heterodyne measurements performed at a temperature of 4.2 K show that high frequency video response extends up to 1.1 THz and the best DSB noise temperatures are 700 K at 900 GHz and 1000 K at 1 THz.

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