Work package 3 – Integration

Here we establish the technology for realisation of high impedance environments and integration of nanowires with the specially designed and developed circuit components. The controllable environment with specific properties is one of the key elements for the observation of CQPS. The nanowires for CQPS must be separated from the external measurement wires with compact and high impedance circuit elements. Small sizes of the elements is a mandatory requirement for successful circuit operation. Micron size inductances with values up to several microhenry will be developed and then integrated with nanowires. This requires solving a number of technological problems, such as, for example, making very long narrow meander structures, fabricating high quality contacts between the thin films of superconductors and nanowires or small Josephson junctions. The development of such components is a challenging task and it will require consolidated efforts of the whole consortium.  Particularly, state-of-the-art nanofabrication processes will be used with thin films of highly disordered superconducting materials, such as NbN.

Another approach, is to make tunable environments – this can be realised by resistances and inductances implemented with CMOS technology. This technology will be developed by VTT and other members will contribute into fabrication of specific components and characterisation.

To optimise the parameters and to describe the integrated circuit behavior theoretical analysis of Josephson junctions with an effect of electromagnetic environment will be carried out. The circuit dynamics with the phase slip junctions will be analysed by direct numerical solving of differential equations with the phase-slip junction and all circuit elements with realistic parameters. All components will be integrated and specific RF environments engineered based on RF simulation results.

A superconducting nanowire embedded in a high inductance environment ( © NPL).