Niobium was deposited by physical vapor deposition (PVD) using e-beam evaporation on bare (100) silicon substrates and SiO(2) surfaces. The formation of niobium silicide was investigated by annealing PVD Nb films in the temperatures range 400-1000 degrees C. At all elevated annealing temperatures the resistivity of Nb silicide is substantially higher than that of Nb. The Nb silicidation as a function of temperature has been investigated and different Nb(X)Si(y) compounds have been characterized. It has been observed that the annealing of the Nb film on Si is accompanied by a strong volume expansion of about 2.5 of the resulting reacted film. The films' structural properties were studied using X-Ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and atomic force microscopy (AFM), which was not previously presented in the context of the extant NbSi literature. The X-Ray diffraction characterization of the Nb on Si sample annealed at 1000 degrees C, showed the presence of hexagonal Nb(5)Si(3) phases, with a dominant peak at the (200) plane, and NbSi(2) phases. Fractal dimension calculations indicate a distinct transition from Stranski-Krastanov to Volmer-Weber film growth for NbSi formation at the annealing temperature of 600 degrees C and above. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3609845] All rights reserved.