Planarized patterning of Y-Ba-Cu-O thin films for multilayer technology

Planarized layers of YBa/sub 2/Cu/sub 3/O/sub 7/ (YBCO) were made by etching trenches in SrTiO/sub 3/ (STO) substrates, laser depositing a YBCO film and mechanically polishing the film down to the substrate surface. These structures exhibited critical temperatures (T/sub c/) of 88 K and a critical-current density (J/sub c/) of 10/sup 6/ A/cm/sup 2/ at 77 K. The planarized surface was smooth, with a maximum height difference between the YBCO and STO of 20 nm. The surfaces were used as templates for epitaxial growth of multilayer insulators of STO and PrBa/sub 2/Cu/sub 3/O/sub 7/ (PBCO) and top YBCO layers. Complete crossovers, free of superconducting shorts, with T/sub c/ of 86 K and critical current density (J/sub c/) of 2/spl times/10/sup 5/ A/cm/sup 2/ were made.<
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