Superconductivity and Electrical transport in NbTiN Films

In this work, we systematically investigate the superconducting properties of Niobium Titanium Nitride (NbTiN) films with different geometries, which at low temperature remain superconducting. NbTiN films with a few nm thickness are widely used in devices such as superconductor-insulator-superconductor (SIS) mixers, superconducting cavities and resonators and superconducting nanowire single-photon detectors (SNSPD). In all these applications, films of varying dimensions are required to achieve optimal performance. The initial thickness of our samples was 125 nm deposited on Silicon substrate. We change the width/length of our samples using lithography and ion milling. We measure and analyze the thickness and width dependence of various superconducting properties of these films. This work was supported by the US Department of Energy through Grant No. DE-FG02-99ER45763.