Ion-beam-induced epitaxial crystallization of amorphous Si implanted w
ith Fe to 18 at. % peak concentration was studied. The structure of th
e specimen was characterized using transmission electron microscopy an
d Rutherford backscattering spectrometry. Both cubic FeSi2 and alpha-F
eSi2 were formed in epitaxy with the Si matrix with two types of orien
tations (fully aligned and twinned). The twins of alpha-FeSi2 and thos
e of cubic FeSi2 were found to have exactly the same type of epitaxial
relationship as for the aligned ones. The thermodynamically stable be
ta-FeSi2 is not formed, demonstrating that ion-beam-induced crystalliz
ation can lead to preferential phase formation as well as to epitaxy.