Process characterization of Niobium based Josephson integrated circuits

Process test chips for Josephson integrated Circuits including refractory metal resistors have been achieved and tested with Niobium based technology made in LETI. Tantalum resistors are lying above niobium base electrode. Such a configuration gives compact logic circuits and very good mechanical bahaviours. An entire 14 layers technology including Nb-Nb2O5- Pb(In) tunnel junctions, control lines and contact pads is being achieved and described. Arrays of 100 interferometers cells, superconductive contacts in series, and other chips for measuring capacitance of junctions and insulators, penetration depths in superconductive materials, resistors are fabricated on sapphire, wafers and tested. Such devices yield a good stability upon thermal cycling and storage at room temperature.