Submicron periodicity Si-CoSi2 structures were fabricated by the directional solidification of eutectic thin films. The films, grown on oxidized Si wafers by laser recrystallization, were prepared without the ablation and cracking previously encountered. Using growth rates of up to 17 cm/s yielded lamellar periods as small as 60 nm. Defects in the lamellar structure were investigated as a function of growth rate, the shape of the solid–liquid interface, and thermal aging.