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Journal of Vacuum Science & Technology B Microelectronics and Nanometer Structures Processing Measurement and Phenomena

Characteristics of a free-standing superconducting nanobridge with an integrated heater fabricated using a self-aligned technique

S.-B. Lee, D. G. Hasko, H. Ahmed

Published Nov 1, 1999• 5 citations
Publisher

Abstract

We report on a novel method of controlling the supercurrent flow in a superconducting weaklink. We have fabricated a free-standing superconducting nanobridge with an integrated NiCr heater. This NiCr layer acts as a self-aligned mask for reactive ion etching and also as the normal metal heating element of the nanobridge. The heater is used to control the critical current of the superconducting weaklink part of the nanobridge; the free-standing nature of the nanobridge reduces the heater power required. We discuss the dependence of the current–voltage characteristics of the superconducting weaklink on heater current. This device has advantages over existing controllable weaklink devices.

DOI
10.1116/1.590990

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We describe the fabrication and digital switching operation of a NOR logic gate that uses a single, dual-input superconducting nanotransistor. The nanotransistor is a weak-link device that has integrated hot-phonon injectors to control its critical current. The fabrication process utilizes a self-aligned method, where the two heaters act as a mask for reactive ion etching to define the device pattern. This device is much simpler to fabricate than previously reported superconducting transistors and the principle of operation makes it possible to use a single nanotransistor, with multiple input heaters, as a NOR logic gate, allowing lower power consumption and improved levels of integration.
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