THE INFLUENCE OF RADIO-FREQUENCY SPUTTER VARIABLES ON THE COMPOSITION OF YBA2CU3O7 FILMS

The compositions and thicknesses of Y-Ba-Cu-O films radio frequency (rf) sputtered from a nonstoichiometric oxide target were determined as a function of deposition conditions. Variations in chamber pressure, rf power, and substrate position were observed to shift the as-deposited cation composition along a single line in the Y-Ba-Cu ternary composition diagram. Deposition rates of up to 24 nm/min were achieved with good cation stoichiometry. Films deposited on YSZ substrates at the optimized sputter conditions produced a zero resistance transition temperature of 88.7 K after a post deposition helium/oxygen heat treatment. Scanning electron microscopy (SEM) and x-ray examination of the films revealed a strongly oriented large-grain polycrystalline microstructure. © 1990, American Vacuum Society. All rights reserved.