Fabrication and DC-Characterization of NbTiN Based SIS Mixers for Use Between 600 and 1200 GHz

摘要: SIS mixers incorporating two-junction, NbTiN tuning-circuits have been designed and fabricated using two different types of tunnel-junctions. The first type tunnel junction-NbTiN/MgO/NbTiN--has the advantage a large gap voltage (5 mV), but has relatively soft I-V characteristic high specific capacitance as compared to Nb/Al-Ox/Nb second junction--Nb/Al-AlNx/NbTiN, is hybrid structure, which many advantages Nb junctions, with slightly larger energy (3.5 mV) more robust thermal properties. A detailed description deposition techniques used in making AlNx devices will be given separate paper. In this paper, we discuss high-quality films, trade-off between stress quality these films. We also details for NbTiN/MgO/NbTiN junctions. measured magnetic-penetration-depth our films SQUID circuits. Using long resonators coupled Josephson propagation velocities microstrip-line circuits; measurement gave us an independent estimate qualitative measure RF-losses microstrip-lines.