Superconducting NbNxCy thin films fabricated with a dual ion-beam sputtering method

We have fabricated refractory superconducting NbNxCy thin films on unheated Si substrates with a low-energy dual ion-beam sputtering technique. Films fabricated with this technique have predominantly B1 crystal structure with maximum Tc ∼13.2 K, resistivity of 80–150 μΩ cm and residual resistance ratio ∼1.0. The use of low ion-beam energies and the absence of substrate heating make this method well suited for producing NbNxCy films for superconducting microelectronic applications.