A fabrication of high quality Nb/AlOx/Nb superconducting tunnel junctions (STJs) for radiation detection is presented. The fabrication process includes a MgO thin film, an underlayer method, a control of critical current, a nitrogen plasma passivation and a SiO2 insulator. Subgap current characteristics of STJs have been investigated and compared with conventional STJs in the temperature range of 0.35K to 4.2K in order to evaluate the junction quality for radiation detection. The STJs made by present process showed extremely high quality junction characteristics of a subgap current density of 0.1pA/μm, a resistance ratio Rd/Rn of 6 × 106 for 200 × 200μm2 STJ with a critical current density of 200A/cm2.
|Number of pages||7|
|Journal||Denshi Gijutsu Sogo Kenkyusho Iho/Bulletin of the Electrotechnical Laboratory|
|Publication status||Published - Dec 1 1997|
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Electrical and Electronic Engineering