Low vacuum vapor process for producing superconductor articles with epitaxial layers
AssigneeAmerican Superconductor Corporation
InventorsLeslie G. Fritzemeier, David M. Buczek
Life of this patent
Estimating the term…
Abstract
A method for fabricating superconductor articles with an epitaxial layer is described. The method can be performed under conditions of relatively high pressure and low substrate surface temperature. The resulting epitaxial layers can demonstrate various advantageous features, including low pore density and/or inclusions with small average particle size diameter.
Claims45
A method of forming an epitaxial layer of a desired material chemically comprising a first species on a deposition surface of a substrate chemically comprising one or more substrate species including at least one species different from the first species, at a predetermined deposition rate, comprising the steps of:
- placing a crystallographically oriented target surface of a substrate in a low vacuum environment, the species present in the target surface substantially consisting of the substrate species, and one or more materials selected from the group consisting of desired native oxides of one or more of the substrate species, and contaminant materials, which include undesired native oxides of one or more of the substrate species and adsorbed surface contaminants;
- heating the target surface to a temperature which is less than about 90% of the melting point of the second material but greater than the threshold temperature for forming an epitaxial layer of the desired material on the substrate material in a high vacuum environment at the predetermined deposition rate;
- directing a layer-forming stream comprising a dispersion of the first species in an inert carrier gas at a first velocity greater than about 1 m/sec toward said target surface through said low vacuum environment;
- directing a dispersion of a beneficially reactive second species at a velocity greater than about 1 m/sec toward said target surface through said low vacuum environment at a velocity substantially similar to said first velocity;
- reacting said second species with one or more of the species present in the target surface to condition the target surface and promote the nucleation of the epitaxial layer;
- depositing a desired material chemically comprising said first species onto said target surface at the predetermined deposition rate to form an epitaxial layer on said substrate;
- and
- depositing an oxide superconductor on said epitaxial layer.
A method of making a superconductor, the method comprising:
- growing an epitaxial buffer layer on a substrate having a temperature that is about the same as a PVD epitaxial growth threshold temperature for a chamber pressure of about 1.times.10.sup.-4 Torr, wherein the growing step is performed in a chamber having a pressure of at least about 1.times.10.sup.-3 Torr;
- and
- depositing on the epitaxial buffer layer a layer of material selected from the group consisting of superconductor materials and precursors of superconductor materials.
A method of making a superconductor, the method comprising the steps of:
- growing an epitaxial buffer layer on a substrate at a rate of at least about 50 Angstroms per second;
- and
- depositing on the epitaxial buffer layer a layer of material selected from the group consisting of superconductor materials and precursors of superconductor materials.
A method of making a superconductor, the method comprising the steps of:
- exposing a surface of a substrate to a conditioning gas that interacts with surface of the substrate to form a conditioned surface of the substrate;
- exposing the conditioned surface of the substrate to a gas beam having a layer forming gas that becomes a component of an epitaxial buffer layer on the conditioned surface of the substrate;
- and
- depositing on the epitaxial buffer layer a layer of material selected from the group consisting of superconductor materials and precursors of superconductor materials.
A method of making a superconductor, the method comprising the steps of:
- growing an epitaxial superconductor layer on a surface of a material having a temperature that is about the same as a PVD epitaxial growth threshold temperature for a chamber pressure of about 1.times.10.sup.-4 torr, wherein the growing step occurs in a chamber having a pressure of at least about 1.times.10.sup.-3 torr, and wherein the material is a buffer layer or a substrate.
Dependencies are inferred from the claim text.