Development of High Temperature Superconducting Josephson Junction Device Technology
Abstract
The DuPont program was successful in generating useful knowledge about thallium cuprate materials, photoresist reflow processing, and radiant heater technology though it did not lead to a new junction technology. Among the achievements of this program was the in situ fabrication of both (Tl,Pb)Sr2CuO5 and (Tl,Pb)Sr2Ca(1-x)Y(x)Cu2O7 films on full two inch wafers. These films were uniform in properties and had quite smooth surfaces as predicted. We were also able to qualify cerium oxide as compatible with the in situ growth process and suitable in a thallium-based multilayer technology. In addition, this project resulted in the first-ever epitaxial thallium cuprate films with copper oxide sheets oriented out of the plane of the film. The program has determined that standard HTS substrates, NdGaO3, CeO2- buffered Al2O3, and LaAlO3, are not ideal for an in situ thallium cuprate junction technology Moreover, we have found that (Tl,Pb) Sr2Ca(1-x)Y(x)Cu2O7 can be as susceptible to electromigration as YBa2Cu3O7. The potentially greater stability of (Tl,Pb)Sr2Ca(1-x)Y(x)Cu2O7 was considered to be one of the key benefits of developing this new technology. In conclusion, the development of stable, reproducible multilayer SNS junctions is no more likely to be achieved with the thallium lead cuprates than with any other HTS materials system.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 09, 1998
- Accession Number
- ADA349144
Entities
People
- Kirsten E. Myers