Iron silicides were grown on Si (111) substrates by Solid Phase Epitaxy (SPE) and Reactive Deposition Epitaxy (RDE) to identify the optimum conditions to obtain the semiconduting beta-FeSi2 phase. The films were produced under different growth and annealing conditions and analyzed in situ and ex situ by X-ray Photoelectron Spectroscopy, and ex situ by Conversion Electron Mossbauer Spectroscopy. The use of these techniques allowed the investigation of different depth regions of the grown layer. Films of the epsilon-FeSi and beta-FeSi2 phases were obtained as well as the mixtures Fe3Si + epsilon-FeSi and epsilon-FeSi + beta-FeSi2. The sequence (FeSi)-Si-3 ->epsilon-FeSi ->beta-FeSi2, was found upon annealing, where the phase transformation occurred due to the migration of silicon atoms from the substrate to the surface region of the grown layer, The best conditions for the phase transformation in SPE samples were met after annealing in the range 700 - 800 degrees C. For the RDE samples, the transition to the beta phase occurred between 600 and 700 degrees C, but pure beta-FeSi2, was obtained only after two hours of annealing at 700 degrees C. (c) 2005 Elsevier B.V. All rights reserved.