Corning Glass Works

Sperry Corporation

Peter L Young

Nicholas Francis Borrelli

Richard M Josephs

Barry F Stein

Arthur J Whitman

Tsing-Chow Wang

John E Sheppard

William E Flannery

Francis P Fehiner

John A Coleman

Ronald A Flowers

During the preparation of a Josephson junction device, one of the steps for making a base electrode is to deposit a superconducting material on a substrate and to anneal the deposited material to make it a continuous homogeneous polycrystalline grain-like electrode material. Ordinarily, the base electrode and the counter electrode materials are deposited in a vacuum system at a vacuum pressure which is below one.times.10.sup.-6 torr to remove all contaminants such as oxygen, oxides of carbon and water vapor. It has been discovered that depositing conventional superconducting base electrode and counter electrode materials in the presence of an inert gas at much high vacuum pressures around 20.times.10-3 torr produce a superior lead-gold superconductive electrode which is substantially immune to thermal cycling.

Method of making high reliability lead-alloy Josephson junction

During the manufacture of Josephson junction devices, it is necessary to provide superconducting layers for electrodes. During the manufacture of semiconductors, it is necessary to provide conductive paths and leads. A layer of conducting metal or superconducting metal may be vacuum deposited in such a manner that any predetermined pattern or shape of normally conducting metal is made transversely non-conducting. The layer metal which is transversely non-conductive is vacuum deposited in the presence of an inert gas at a pressure which is high enough to cause the evaporated and deposited metal to form islands of conductive metal separated by insulating voids to provide gross electrical anisotropy.

Method of making planarizing non-conductive layers employing conductive

A novel method of depositing the oxide barrier junction on a base electrode of a Josephson junction device is provided. An ionized oxygen plasma region is generated juxtaposed the surface of the base electrode to be oxidized. The pressure of the oxygen in the vacuum chamber is held at a predetermined high pressure where the zero voltage supercurrent is found to be independent of oxygen pressure variations and the flow of oxygen through the vacuum chamber is stabilized at the optimum minimum necessary for growth of the oxide barrier junction. The oxide barrier junctions so produced have consistent and predictable supercurrent densities.

Method of controlling the supercurrent of a Josephson junction device

An apparatus comprising a rotating substrate holder is provided. The rotating substrate holder is hollow and adapted to receive liquid gas such as nitrogen to cool the substrate to cryogenic temperatures. The novel substrate holder is supported inside of a vacuum chamber by a thin wall tube which is sealed with a liquid rotating seal at the point where it passes completely through the top wall of the vacuum chamber. The novel thin wall tube support provides access to the hollow substrate holder from outside the vacuum chamber and provides temperature isolation of the liquid in the substrate holder so that the liquid rotating seals are maintained at operable elevated temperatures.

Rotating liquid nitrogen cooled substrate holder

An improved method of anodization of thin films for the fabrication of superconducting devices. An electrically conducting contact layer is formed over a substrate between an electrically conducting object layer and the substrate. Also, an electrically insulating layer is formed between the object layer and the contact layer. The contact layer is connected to a power supply and at least a preselected portion of the object layer is anodized to a predetermined thickness. This may include anodizing all of some preselected portions through the complete thickness of the object layer. A pattern of hardened photoresist on the object layer provides portions not protected by the pattern. When anodization of the electrically conducting object layer takes place, the resulting anodized portion is thicker than the thickness of the portion of the object layer that it replaces. The present invention further includes reducing the preselected portion of the object layer to be anodized by a predetermined amount before anodizing so that when anodization is complete, the resulting partially anodized partially conducting object layer is substantially planar. Alternatively, the thickness of the anodized preselected portions can be reduced after anodizing by a predetermined amount to cause the layer to be substantially planar. The same pattern of hardened photoresist can be used when reducing the thickness of portions of the object layer or anodized preselected portions.

Superconducting circuit fabrication

During the manufacture of Josephson superconducting devices, it is necessary to provide on a substrate a base electrode, a counter electrode and a small tunnel barrier area therebetween. A novel method of making all three of these active elements in the same vacuum chamber without having to remove the substrate from the vacuum chamber is provided so that the tunnel barrier area is accurately made to a predetermined size and without the danger of contamination. The novel structure is made as a substantially planarized laminate in the vacuum chamber and the tunnel barrier area is defined in a supplemental step.

Method of making improved tunnel barriers for superconducting Josephson

The present invention teaches a method of planarizing built-up vacuum deposited surfaces or areas on Josephson junction and semiconductor devices so that successively deposited layers do not replicate the undulations of previous layers. After a surface layer is deposited in a vacuum system and part of the surface is etched, a raised surface is generated. A photoresist lift-off stencil is applied to the surface to be preserved and the material to be removed is removed by isotropically etching so as to leave an overhang or ledge of photoresist material over the area of the material retained. A new layer of material is now deposited by vacuum deposition so as to almost fill the area to be planarized. A small gap remains between the top of the new material being vacuum deposited and the botton of the photoresist stencil so that solvent can be introduced to the stencil. When the photoresist stencil is removed, the top of surface being preserved is substantially planar with the new layer of material.

Method of making planarized Josephson junction devices

During the process of vacuum deposition, metals and materials are evaporated at a point source so as to create a vapor which is dispersed isotropically. Layers of the evaporating material are deposited as built-up layers which have sharp vertical edges or steps at the areas defined by the photoresist stencil. When the line of sight of the depositing material is from an oblique angle, the layer being deposited can have a negative slope which appears as an undercut edge. The present invention employs a lift-off overhang photoresist stencil in conjunction with a relatively high pressure of inert gas in the vacuum chamber so as to promote collision of the evaporated atoms and molecules with the inert gas. The colliding atoms and molecules of the evaporating material no longer appear to be originating from a point source but appear to originate from an extended area in the end of the vacuum chamber and deposit under the overhang photoresist stencil so as to provide symmetrical positive slope step changes at the edges of the material being deposited.

Method of producing positive slope step changes on vacuum deposited

An optical information storage medium comprising a thin, optically darkenable film containing silver, lead, chlorine and oxygen, produced by vapor-depositing AgCl and PbO in specified proportions on a substrate for the film, is described.

Archival optical recording medium

A photosensitive medium suitable for storing positive images and a method of using it are provided, the medium being a multilayer film comprising SnO.sub.2 and doped silver chloride and the method comprising an exposure step for negative imaging and a heating step for image reversal.

Positive imaging method using doped silver halide medium

Methods for making photosensitive thin film structures comprising one or more metal-dielectric layers, produced by the sequential deposition of discontinuous metal island films and transparent covering films containing selected dielectric acceptor materials, and the use of the photosensitive thin film structures to record full-color and/or dichroic images, are described.

Photosensitive film and methods

An ultraviolet-sensitive optical information recording material comprising doped silver chloride and tin oxide which exhibits high ultraviolet darkening sensitivity and good resistance to darkening or bleaching by visible light, and a method for optically recording information in permanent, optically-readable form in such a material by direct writing without chemical development, are described.

Polycrystalline tin oxide-silver chloride-cadmium chloride UV

Electron beam-sensitive films containing silver chloride, cadmium chloride and tin oxide, and the use of such films to provide optical masks by selective film darkening with an electron beam, are described.

Tin oxide, cadmium chloride doped silver chloride electron beam

A photosensitive medium for storing optical information relating to the intensity and polarization of incident light, consisting of an inorganic multilayer film comprising multiple thin layers of silver chloride to which additive coloration has been imparted by chemical means, is described.

Photosensitive medium for optical information storage

Optically bleachable multilayer films containing additively colored silver chloride which exhibit high infrared transmittance and good bleaching sensitivity, and optical information storage media incorporating such films, are described.

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North Wales, PA, United States of America

Peter L Young