Abstract:

NbN/MgO/NbN Josephson tunnel junctions have been prepared using various barrier preparation conditions. The energy of the sputtered MgO particles arriving at the substrate was found to be the most important parameter. Tunnel junctions (10*10 mu m2) with Vm values of up to 23 mV have been fabricated. The optimized NbN/MgO/NbN junction process is extended to a reliable whole-wafer process for DC SQUID fabrication.