Ultrathin (∼ 1.5 nm) epitaxial films of P-FeSi2were grown by two methods; by sequential deposition of ultrathin amorphous Si and Fe followed by annealing and by mere Fe deposition followed by annealing. During the various stages of the growth process the lattice structure, composition and morphology of the films were investigated by medium-energy ion scattering in conjunction with shadowing and blocking.
At RT the deposited Fe reacts with the Si(001) substrate and forms a continuous film of average composition FeSi for both growth methods. Upon annealing to 670 K a conversion into epitaxial β-FeSi2 takes place. β-FeSi2 films grown by mere Fe deposition are composites of two orientational domains. On the other hand, films grown by sequential Si and Fe deposition are essentially of single orientation (>90% A orientation).