Fabrication of high quality Nb/AlO/Nb superconducting tunnel junctions for radiation detection

摘要

A fabrication of high quality Nb/AlO_x/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 SiO_2 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.