Iron-silicides were grown on Si by reactive deposition epitaxy method and by conventional solid phase reaction. The morphology of silicides was investigated by optical microscopy, scanning electron microscopy and by atomic force microscopy. The phases formed were identified by X-ray diffraction. The thickness of the evaporated Fe films ranged from 1.5 to 30 nm and the in situ heat treatments were carried out between 500 and 800 degreesC. Self-assembled, island like, oriented beta-FeSi2 and alpha-FeSi2 were found to grow on Si(100) substrates under 15 nm initial Fe thickness. The size of the islands was between 20 and 500 nm, and their shape varied from circular to faceted triangular and quadratic depending on the Fe thickness and on the annealing. Above 20 nm evaporated Fe thickness, the samples show islands of beta-FeSi2 phase grown into the FeSi matrix indicating a nucleation controlled type transition of the FeSi to beta-FeSi2 phase. (C) 2003 Elsevier B.V. All rights reserved.