The morphology and defect structures associated with thin NiSi2 films prepared on Si(100) were investigated. Facets were found to be a common defect structure at the interface unless stoichiometric co-deposition of Ni and Si was performed. Annealing thin, uniform NiSi2 layers prepared by stoichiometric co-deposition to temperatures ≥ 700°C yielded epitaxial films of high crystalline perfection. Films in which the deposition was off-stoichiometric exhibited a variety of defect structures. In addition to facets at the interface, networks of meandering micro-twins or stacking faults were observed in highly Ni-rich films, while pinholes were observed in Si-rich films. Facets at the interface were found to be eliminated by annealing at temperatures ≥ - 750°C, indicating that the planar NiSi2/Si(100) interface is energetically stable with respect to the formation of NiSi2(111) facets. Through manipulation of the film growth kinetics, NiSi2/Si(100) interfaces with arbitrary facet densities were produced. Partially faceted NiSi2/Si(100) interfaces represent ideal experimental systems for revealing the effects of Schottky barrier inhomogeneity on the electrical measurements of metal/semiconductor contacts.