Browse Prior Art Database

Quiteron Process Steps

IP.com Disclosure Number: IPCOM000045148D
Original Publication Date: 1983-Feb-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Drake, RE: AUTHOR [+5]

Abstract

A cryogenic, three-terminal inverting switch having transistor like properties can be fabricated, and is termed a QUITERON. It is comprised of three superconducting layers separated by two insulating barriers, and has the structure S(1) -I(1) -S(2) -I(2) -S(3), where S(1), S(2) and S(3) are thin superconducting films having superconducting band gaps D(1), D(2), and D(3)4. I(1) and I(2) are insulating barriers. Device operation depends upon the proper choice of parameters, and is achieved by drastically changing D(2), driving it to zero by the injection of excess quasi particles. In order to make this device, a high yield LSI fabrication process is described in which breakable bridges are used to provide selective anodization.

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Quiteron Process Steps

A cryogenic, three-terminal inverting switch having transistor like properties can be fabricated, and is termed a QUITERON. It is comprised of three superconducting layers separated by two insulating barriers, and has the structure S(1) -I(1) -S(2) -I(2) -S(3), where S(1), S(2) and S(3) are thin superconducting films having superconducting band gaps D(1), D(2), and D(3)4. I(1) and I(2) are insulating barriers. Device operation depends upon the proper choice of parameters, and is achieved by drastically changing D(2), driving it to zero by the injection of excess quasi particles. In order to make this device, a high yield LSI fabrication process is described in which breakable bridges are used to provide selective anodization.

In this process, two tunnel junctions are vertically disposed, the electrodes of which are electrically isolated and can be accessed for testing. The groundplane acts as a groundplane to striplines, and at the same time is an electrically isolated base electrode (S(1)) to the injector junction. Since the band gap of S(2) is drastically changed by injection of quasi particles, it is required that S(2) be as thin as possible. This creates a problem, since S(2) is in the middle of the device and step coverage becomes a constraint on the minimum S(2) thickness. The individual process steps eliminate this problem.

In the figure, S(1) is an island on which I(1) is formed by selective anodization. S(2) is deposited through a...