FORMATION OF IRONSILICIDE ON SI(001)

Ultrathin epitaxial films of beta-FeSi, were grown on Si(001) by room temperature (RT) deposition of Fe followed by annealing. During the va rious stages of the growth process the lattice structure, composition and morphology of the films were investigated by medium-energy ion sca ttering in conjunction with shadowing and blocking. At RT the deposite d Fe reacts with the Si(001) substrate and forms a continuous film of average composition FeSi, or Fe5Si3, depending on the deposited amount of Fe. After annealing the FeSi film to 670 K, a conversion into beta -FeSi2 has taken place and the film is no longer continuous. The beta- FeSi2 films grown are composites of two azimuthal orientations with re spect to the substrate: the predominant A orientation with beta-FeSi2 [010] parallel-to Si[110] and the B orientation with beta-FeSi2 [010] parallel-to Si[100].