Electrical resistivity of polycrystalline niobium nitride films

The electrical resistivity of magnetron-sputtered polycrystalline NbN thin films has been measured as a function of the temperature for a variety of samples exhibiting different grain structures. The data are very well described by a model recently proposed by Reiss, Vancea, and Hoffman for granular metallic systems. The model correctly predicts the observed negative temperature coefficient of resistivity and the occurrence of a minimum in the temperature dependence of the resistivity.