Planar epitaxial films of SnO.sub.2
AssigneeThe United States of America as represented by the Secretary of Commerce
InventorsStephen Semancik, Richard E. Cavicchi
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Abstract
A planar epitaxial film of tin oxide has low defect density, high purity, crystalline rutile unit cell structure, one crystalline orientation, controlled stoichiometry, extended lateral dimensions, extremely smooth surface morphology, a high degree of atomic order extending to the surface of the film and is colorless and transparent. The film is made by a method which includes reactive sputter deposition. The films can be used in chemical sensors as well as in numerous other applications.
Claims14
A thin film structure comprising:
- a smooth planar epitaxial film of SnO.sub.2 having low defect density, rutile unit cell structure, one crystalline orientation, controlled stoichiometry, extended lateral dimensions as compared to single crystals, atomic order extending to the surface of said film and being of extremely smooth surface morphology, colorless and transparent.
A thin film structure comprising:
- a smooth planar epitaxial film of SnO.sub.2 having low defect density, rutile unit cell structure, one crystalline orientation, controlled stoichiometry, extended lateral dimensions as compared to single crystals, atomic order extending to the surface of said film and being of extremely smooth surface morphology, colorless and transparent;
- and
- a crystalline substrate selected from the group consisting of sapphire (1102), sapphire (0001) and TiO.sub.2 (110) on which the film is situated.
A thin film structure comprising:
- a smooth planar epitaxial film of SnO.sub.2 having low defect density, rutile unit cell structure, one crystalline orientation, controlled stoichiometry, extended lateral dimensions as compared to single crystals, atomic order extending to the surface of said film and being of extremely smooth surface morphology, colorless and transparent;
- an insulating substrate having a crystalline structure on which the film is situated;
- and
- at least 3 monolayer equivalents of a metal selected from the group consisting of iron, nickel, ruthenium, molybdenum, tungsten, niobium, copper, tantalum, silver, palladium and platinum.
A chemical sensor element comprising:
- a smooth planar epitaxial film of SnO.sub.2 having low defect density, rutile unit cell structure, one crystalline orientation, controlled stoichiometry, extended lateral dimensions as compared to single crystals, atomic order extending to the surface of said film and being of extremely smooth surface morphology, colorless and transparent;
- an insulating substrate having a crystalline structure on which the film is situated;
- and
- at least one monolayer equivalent of metal dispersed on the film of SnO.sub.2.
A plurality of chemical sensor elements, comprising:
- a smooth planar epitaxial film of SnO.sub.2 having low defect density, rutile unit cell structure, one crystalline orientation, controlled stoichiometry, extended lateral dimensions as compared to single crystals, atomic order extending to the surface of said film and being of extremely smooth surface morphology, colorless and transparent;
- an insulating substrate having a crystalline structure on which the film is situated;
- and
- a plurality of at least one monolayer equivalent of metal dispersed on the film of SnO.sub.2.
Dependencies are inferred from the claim text.