Rapid thermal annealing (RTA) of Fe-Si layers co-deposited on n- and p- type Si (100) and Si-capped relaxed Si0.6Ge0.4 (100) substrates was studied. Relaxed (100) Si0.6Ge0.4 epitaxial layers represent a pseudo-matched substrate for the β-FeSi2 phase. Fe-Si layers with a 1:2 composition ratio were deposited at room temperature in an MBE system. Samples were then subjected to a rapid thermal annealing in a H2/N2-atmosphere in the temperature range between 500 and 800 °C. Conversion electron Mössbauer spectroscopy showed that the layers consist of the β-FeSi2 phase. Nomarski microscopy revealed crystal grains of the diameter from 5 to 10 μm. Cross-section transmission electron microscopy study found smooth surfaces and interfaces. No significant structural defects were found inside the grains. Differences between current-voltage characteristics of simple devices prepared on these layers agree with the trends expected from their band diagrams.