Superconducting properties, electrical resistivities, and structure of NbN thin films

Abstract
Superconductingproperties and electrical resistivities of NbN thin films have been studied as a function of sputtering parameters, filmstructure, and composition. A good correlation exists between superconductingTc 's and filmstructure and composition regardless of the sputtering conditions used to achieve this structure. The most important parameters affecting Tc are lattice parameter,crystal structure, island structure, and impurity content. Substrate temperature, Ar/N2 ratio, and impurity content are the principal sputtering parameters affecting filmstructure, and thus Tc .