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Josephson Gate Structure

IP.com Disclosure Number: IPCOM000081712D
Original Publication Date: 1974-Jul-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Schlig, ES: AUTHOR

Abstract

Present practice in design of in-line Josephson gates, is to make circuit connections to the top and bottom conductors of the junction at opposite ends of the junction. Connecting the external circuit to the same end of the top and bottom conductors of the junction is taught herein. The new structure has device characteristics virtually identical to those of the old structure wherein, due to the ground plane, current in the bottom electrode is constrained to flow on the underside of that electrode the entire length of the gate, and finally enters the junction proper at the same end as the top electrode current.

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Josephson Gate Structure

Present practice in design of in-line Josephson gates, is to make circuit connections to the top and bottom conductors of the junction at opposite ends of the junction. Connecting the external circuit to the same end of the top and bottom conductors of the junction is taught herein. The new structure has device characteristics virtually identical to those of the old structure wherein, due to the ground plane, current in the bottom electrode is constrained to flow on the underside of that electrode the entire length of the gate, and finally enters the junction proper at the same end as the top electrode current.

In the new structure shown in Figs. 1 and 2 in plan and cross-sectional views, respectively, the current in the overlying top electrode 1 causes the current in bottom electrode 2 to divert to the top face, at the end of the junction to which connections are made. Actual junction current distributions in proximity to the thin oxide barrier 3 are the same in both structures.

An advantage of the new structure is that mutual inductive coupling between control lines 6 and gate lines formed from electrodes 1,2 is substantially reduced, since its sense is opposite in the top and bottom electrodes relative to their circuit. In addition, the length of the circuit and, therefore, delay, are reduced by the difference between the length and width of the gate. Using this approach, connections 4,5 which are made to top electrode 1 and bottom ele...