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A Cryotron Structure for Use With Epoxy Insulation

IP.com Disclosure Number: IPCOM000095886D
Original Publication Date: 1964-Aug-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Jones, RE: AUTHOR

Abstract

This is a method for fabricating thin film cryotrons onto an organic type base rather than on a silicon oxide type base.

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A Cryotron Structure for Use With Epoxy Insulation

This is a method for fabricating thin film cryotrons onto an organic type base rather than on a silicon oxide type base.

When a thin film of superconductive material is deposited onto a suitable base 2 as in A, due to the penetration of deposited material beyond the edges of a mask, the gate material 4 is deposited with a thick central portion p and thin side portions t. When the gate 4 is subsequently driven resistive, the thick portion p is driven resistive sooner than the thin portions t so that one obtains a superconducting to normal transition as shown by the curve c of B. To obtain the sharp transition represented by the dotted curve s, it is necessary to make the gate 4 of uniform thickness.

To obtain such uniformity, a layer of silver 6 is deposited onto an epoxy layer 2, such deposition being 100 Angstroms thick. Another layer also 100 Angstroms thick of germanium is deposited onto the silver, such germanium layer 8 being narrower than the silver layer. A final layer 10 is deposited through a mask onto the germanium layer 8. This final layer is the gate material and can be made of tin or indium. The indium or tin has the effect of antinucleating the silver layer 6, so that the edges of the silver layer 6 are broken up into large discontinuous grains of silver. The antinucleating effect removes the thin edges, such as edges t shown in A, so that a cryotron gate having a sharp superconductive to normal tra...