Effects of processing on electrical properties of YBa2Cu3O7 films. I. Postdeposition anneal process

• Published in: Journal of vacuum science & technology. A, Vacuum, surfaces, and films Vol. 11; no. 3; pp. 574 - 579
• Main Authors: Sheats, James R., Taber, Robert C., Merchant, Paul, Amano, Jun
• Format: Journal Article
• Language: English
• Published: Melville, NY American Institute of Physics 01-05-1993
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Physics; Superconducting films and low-dimensional structures; Superconductivity; CRITICAL CURRENT; YBa2Cu3O7; YTTRIUM OXIDES; COPPER OXIDES; HIGH−TC SUPERCONDUCTORS; ANNEALING; SPUTTERING; CURRENT DENSITY; QUATERNARY COMPOUNDS; SUPERCONDUCTING FILMS; BARIUM OXIDES; SURFACE CONDUCTIVITY; Electrical conductivity; Transition metal Compounds; Microwave; Experimental study; Controlled atmosphere; Surface treatment; Inorganic compound; Optical conductivity; Thin film; Critical current; Surface conductivity; Thermal annealing; Barium Copper Yttrium Oxides Mixed; High temperature superconductor
• ISSN: 0734-2101; 1520-8559
• DOI: 10.1116/1.578774

The effects of several patterning process steps on the critical current density J
c
and microwave surface resistance R
s
of a‐axis oriented films of YBa2Cu3O7 on LaAlO3 are described. The films were prepared by cosputtering from Y, BaF2, and Cu targets, followed by annealing in water‐saturated O2. J
c
and R
s
parameters were measured by mutual inductance and parallel plate resonator techniques, respectively, so that the films did not require patterning for the measurement. Application of a polymer film followed by stripping in acetone caused modest degradation, while stripping with an O2 plasma resulted in no change in the parameters. Brief ion milling, as well as baking at 185 °C with polymer film present, caused severe degradation; other treatments had intermediate effects. The degree of degradation suggests that the surface damage results in secondary effects that penetrate well into the film. A formula is derived for the change in R
s
due to a surface layer, providing a quantitative comparison to experiment.