Abstract
The present state of art of metalorganic chemical vapor deposition (MOCVD) of thin films of oxide superconductors is reviewed. A very smooth surface film of c-axis oriented YBa_2Cu_30_x(YBCO) with roughness of less than monomolecular layer over 10μm×10μm, free of precipitates, has been obtained by atomic layer-by-layer MOCVD on a SrTi0_3 substrate at 650℃. A very large terrace length of 0.3-O.5μm may be due to the enhanced migration of chemical species on the surface. The result of an attempt to prepare YBCO films with a larger terrace width surface using lattice-matched NdGaO_3 substrates is discussed. The correlation between boulder formation and dislocations in the substrate is clarified and methods for eliminating boulders are proposed.
