Sperry Corporation

Barry F Stein

Peter L Young

Martin J Casey

Herman E Wetterskog

Richard M Josephs

Tsing-Chow Wang

John E Sheppard

William E Flannery

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

A bubble memory device and method of fabrication are disclosed which establish that there is a correlation between bubble memory performance and the properties of a quartz film, which is interposed between the bubble film and metallic overlays, namely, the permalloy and/or conductor layers of the device. Specifically, it has been established that there is a correlation between improved device performance and a low p-etch rate which is a measurement that establishes certain elastic constants of the quartz (i.e., the response of the device to stress).

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Dresher, PA, United States of America

Barry F Stein