Epitaxial NiSi2 layers have been grown onto (100) and (111) Si substrates by multiple scan electron beam annealing. The formation and the composition of the silicides have been analyzed by Rutherford backscattering techniques and by electron diffractionobservation. The phase and the composition of the silicides depend on the power density of the electron beam. Under the optimum conditions, epitaxial NiSi2 layers with a high surface morphology can be grown. An attempt has been made to form crystalline Si—NiSi2—Si heterostructures and the preliminary data are also presented.