The growth of high quality semiconducting beta-FeSi2 layers on silicon
substrates is rather difficult due to a large lattice mismatch [up to
approximately 5.5% on Si(111)] and very different crystallographic st
ructure (orthorhombic structure on top of the diamond one). We report
on a new method using the chemical beam epitaxy (CBE) technique to sta
bilize at first the tetragonal alpha-FeSi2 phase (lattice mismatch app
roximately 0.8% on Si(111)) at approximately 550-degrees-C. Then a pos
t-annealing up to approximately 650-degrees-C induces a phase transiti
on from the alpha to beta phase via a tremendous coalescence of numero
us small metallic alpha grains (approximately 200 angstrom width) into
large semiconducting beta-grains (less-than-or-equal-to 1 mum width)
of high quality, suitable for Si integrated optoelectronic technology.