TECHNOLOGY BRIEF

SYNTHESIS OF YBa2Cu307 USING SUBATMOSPHERIC PROCESSING

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Description: The present invention provides a method for the manufacture of high quality crystalline YBa2Cu3O7 (YBCO) films that are more uniform and which can be grown at relatively high growth rates using substantially reduced water pressure and substantially reduced total pressure than currently practiced methods. In this modification of the BaF2 annealing technique, YBCO precursor films are annealed at a total pressure of less then 20 Torr and water vapor partial pressure is reduced more than 1000-fold. Growth rates remain comparable to growth rates achieved at atmospheric pressure.

Commercial and Technical Merit: Reduction of the water vapor partial pressure serves to decrease the potentially deleterious effects of water on the metallic substrate, buffer layer and YBCO films. An additional benefit is a decrease in the residence time of the gasses when annealing at sub-atmospheric pressures but using the same gas flow as in an atmospheric pressure annealing chamber. A decrease in residence time allows impurity gasses and gaseous by-products to be swept out of the sub-atmospheric annealing chamber much more quickly. This results in a cleaner and more uniform YBCO film.

Competitive Advantage: Useful YBCO films must carry high currents. This requires films 5 microns thick or greater. Films also must be grown at reasonably fast rates. This process allows growth of films with high critical current densities at rates of up to 5 Angstroms/sec.

Inventor: Harold Weismann

Patent Status: U.S. Patent 6,794,339

Related publications: "High Rate Deposition of 5µm Thick Yba2Cu3O7 Films Using the BaF2 Post Annealing Process", Solovyov et al., IEEE Transactions on Applied Superconductivity, 9(2) June 1999.

Licensing Status: Available exclusively or non-exclusively