Organometallic chemical vapor deposition of high T c superconducting Bi-Sr-Ca-Cu-O films

Films of the high Tc Bi-Sr-Ca-Cu-O superconductor have been prepared by organometallic chemical vapor deposition using the volatile metalorganic precursors Cu(acetylacetonate)2 , Sr(dipivaloylmethanate)2 , and Ca(dipivaloylmethanate)2, and triphenylbismuth. Deposition is carried out at 2 Torr with argon as the carrier gas and oxygen and water vapor as reactants. Film growth rates of 2–3 μm/h are achieved. After annealing under oxygen, energy dispersive x-ray analysis and x-ray diffraction data reveal that such films on [100] single-crystal MgO consist predominantly of the Bi2(Sr,Ca)3Cu2Ox, Tc=85 K, phase and have preferential orientation of the crystallite c axes perpendicular to the substrate surface. Four-probe resistivity measurements reveal the onset of film superconductivity at ∼110 K and zero resistance by 75 K.