Browse Prior Art Database

Fabrication of Injection Controlled Superconducting Links

IP.com Disclosure Number: IPCOM000034182D
Original Publication Date: 1989-Jan-01
Included in the Prior Art Database: 2005-Jan-26
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Bumble, B: AUTHOR [+3]

Abstract

Improved current density and more efficient cooling of the circuit line (link) of three terminal injection-controlled superconducting device, called a HOTPROP, is achieved by blanket depositing the link on the substrate instead of using lift-off processing over edge structure. (Image Omitted) Referring to Fig. 1a, link metallurgy 1, niobium nitride (or some other superconductor which exhibits combined high critical current and resistivity), is blanket deposited on a crystalline insulating substrate 2. An etch mask of aluminum is deposited after a resist pattern is formed via sub-micron lithography. The link is patterned by reactive ion etching (RIE) and the aluminum removed chemically afterward.

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Fabrication of Injection Controlled Superconducting Links

Improved current density and more efficient cooling of the circuit line (link) of three terminal injection-controlled superconducting device, called a HOTPROP, is achieved by blanket depositing the link on the substrate instead of using lift-off processing over edge structure.

(Image Omitted)

Referring to Fig. 1a, link metallurgy 1, niobium nitride (or some other superconductor which exhibits combined high critical current and resistivity), is blanket deposited on a crystalline insulating substrate 2. An etch mask of aluminum is deposited after a resist pattern is formed via sub-micron lithography. The link is patterned by reactive ion etching (RIE) and the aluminum removed chemically afterward. Thereafter, sub-mircon lithography is used to provide a lift- off pattern exposing a barrier site on which is grown tunnel barrier 3 and over which is deposited injector metallurgy 4 and insulating cap 5 defined by the lift-off pattern. A conformal coating 6 of insulating film is deposited, as shown in Fig. 1b. With standard large-scale integration lithography, a lift-off stencil pattern for large heat sink banks is formed and insulating film 6 is directionally etched by RIE or ion beam etching with the end point detection of metallurgy 1. This is shown in Fig. 1c. Finally, metal layer 7 is angle deposited for the large banks and defined with the lift-off pattern, as shown in Fig 1d. The resulting HOTPROP appears a...