Fe silicide growth on a Si(111) surface has been characterized by Weissenberg RHEED. The silicides were grown in the present study via two fundamental methods, reactive deposition epitaxy (RDE) and solid phase epitaxy (SPE), with various deposition amounts of Fe. The silicide species and its epitaxial orientation were determined from three-dimensional diffraction patterns obtained using Weissenberg RHEED. It was found that only α-FeSi₂ islands grew by the RDE method. Both α-FeSi₂ and β-FeSi₂ islands grew by the SPE method. The proportion of β-FeSi₂ increased with increasing Fe deposition amount, until only β-FeSi₂ was finally observed. The present results could be explained by the surface or interface reaction model wherein the reaction at the Si surface and at the Fe/Si solid interface caused α-FeSi₂ and β-FeSi₂ growth, respectively. [DOI: 10.1380/ejssnt.2009.866]