Fabrication of Superconducting Devices and Circuits

J. M. De Teresa

Abstract In this Perspective article, we evaluate the current state of research on the use of focused electron and ion beams to directly fabricate nanoscale superconducting devices with application in quantum technologies. First, the article introduces the main superconducting devices and their fabrication by means of standard lithography techniques such as optical lithography and electron beam lithography. Then, focused ion beam patterning of superconductors through milling or irradiation is shown, as well as the growth of superconducting devices by means of focused electron and ion beam induced deposition. We suggest that the key benefits of these resist-free direct-growth techniques for quantum technologies include the ability to make electrical nanocontacts and circuit edit, fabrication of high-resolution superconducting resonators, creation of Josephson junctions and superconducting quantum interference device (SQUIDs) for on-tip sensors, patterning of high-Tc SQUIDs and other superconducting circuits, and the exploration of fluxtronics and topological superconductivity.

J.C. Gallop, Luning Hao, J.C. Macfarlane

A. Rebello, N.Y. Klein, L. M. Ruela +4 more

Superconducting circuits have emerged as a highly promising platform for quantum computing, among other divices based on Josephson junctions. The fabrication and testing of these devices requires especiallized nanofabrication facilities and milikelvin range testing equipment. In the search for the fabrication of these devices we have ran into limitations which forced us into creative solutions for the fabrications of these superconducting circuits and Josephson Junctions. Furthermore the development of these technologies allows for application in a wide range of research fields such as quantum computing, magnonics, micro-electromechanical systems and more.

W.S. Khokle, Ravish Gupta

T. M. Klapwijk, D. R. Heslinga, Wim M. van Huffelen

Shuichi Tahara, Shinichi Yorozu, Y. Kameda +5 more

Superconducting devices have intrinsically superior characteristics to those of semiconductor devices. Presently, we can fabricate more than twenty thousand junctions on one chip using niobium technology. We have demonstrated the operation of a network system with a superconducting interconnection chip using voltage-state logic. Single flux quantum devices are promising for future superconducting applications because the clock frequency of SFQ logic is higher than that of voltage-state. We have proposed a high-end switch based on hybrid architecture using optical devices, semiconductors and SFQ devices. To demonstrate the high-speed operation of SFQ circuits, we developed an arbiter circuit that uses SFQ components and the arbiter circuit operates at 60 GHz. We also have developed a high Tc superconducting (HTS) SFQ sampler system for observing ultra-fast signal waveforms. In addition, we will discuss the prospects of future superconducting devices based on the fabrication technologies we developed.