Superconducting titanium nitride thin films are used in many quantum applications due to their large kinetic inductance. Here we prepared thin films using DC reactive magnetron sputtering at room temperature, with an RF bias applied to the substrate to systematically control film growth. By adjusting the substrate RF bias, the degree and length scale of disorder are tuned, leading to pronounced changes in film microstructure and superconducting properties.
We observe a dome-shaped dependence of the superconducting critical temperature Tc on RF bias , accompanied by a minimum in the superconducting coherence length near the peak of the Tc dome.
The mesoscopic control of disorder and microstructure provides a pathway for engineering TiN films with superconducting properties that are desirable for applications requiring high normal-state sheet resistance in fully gapped superconductors, such as superconducting resonators and high kinetic inductance devices. The findings are published in APL-Materials