The solid-phase reaction between Si(1 1 1) substrate and the crystalline, (0 0 2) oriented Co him was studied by annealing the samples at temperatures ranging from 470 to 850 degrees C. The preferential orientations of Co2Si(0 2 1) and CoSi(2 1 0) have been reported and theoretical explanations have been given by comparing the arrangement of atoms on Co2Si(0 2 1) with that on Co(0 0 2), as well as CoSi(2 1 0) with Co(0 0 2) and Si(1 1 1). The co-existence of the three silicides was observed after rapid thermal annealing (RTA) at 600 degrees C. Pure CoSi2 film was obtained after RTA at 700 degrees C and with the increase of annealing temperature, the (1 1 1) preferential orientation of CoSi2 film becomes stronger. Single-crystal CoSi2 film was obtained by RTA at 850 degrees C and comparison with previous reports suggests that reaction between the crystalline Co him and Si(1 1 1) substrate may be beneficial for the epitaxial growth of CoSi2 on Si(1 1 1) substrate.