Microwave losses in kinetic-inductance devices fabricated from NbCN/MgO/NbCN trilayers

The microwave losses in kinetic-inductance devices fabricated from NbCN/MgO/NbCN trilayers are being investigated. The loss tangent of an amorphous MgO thin film has been measured for frequencies near 10 GHz with a kinetic-inductance stub filter. The value of 0.0031 represents a factor of approximately 3 improvement over Si:H films found for a similar kinetic-inductance structure operating in a similar frequency range. Further improvement in the dielectric is also discussed. Other properties of the superconducting trilayer structure are consistent with previous results.<
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