Thin uniform beta-FeSi2 films were fabricated on ion irradiated Si(100) substrates to achieve an atomically flat interface. Ion irradiation produces a surface with more defects than chemical etching; however, it is expected that the presence of defects can promote the formation of compound films such as beta-FeSi2 that require interdiffusion and reaction processes. However, excess defects can also result in random nucleation, poor crystallinity and a rough interface. Cross-sectional transmission electron microscopy was used to determine the optimum conditions for ion irradiation of the substrate to obtain a clear beta-FeSi2/Si interface. (C) 2011 Elsevier ay. All rights reserved.