- Conference date: 24−26 Sep 1991
- Location: Buffalo, New York (USA)
Superconducting YBa2 Cu 3O7 films have been grown in situ by simultaneously sputtering from Y, BaCu, and Cu targets. One advantage of such metal cosputtering is the higher deposition rate compared to oxide target sputtering. Another advantage is the ability to control the individual element rates to vary composition or to substitute for any of the metals without interrupting film growth and without making additional composite targets. To prevent film damage due to oxygen ion bombardment during film growth which was observed when the sputter guns faced the substrate (on‐axis sputtering), an off‐axis geometry was used. One disadvantage we found with in situ metal cosputtering was that reproducibility of stoichiometries was difficult because of the presence of oxygen at the targets. To minimize the oxygen partial pressure at the targets during sputtering, the chamber was differentially pumped. Films grown in the off‐axis geometry with a substrate temperature near 700 °C, a chamber pressure of 7.5 mT, and an O2:Ar flow ratio of 1:50 had zero resistance at 85 K. Results for on‐axis, composite target magnetron sputtering with a high‐strength magnet are also presented. These results are not promising.
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