Iron silicides formation on Si (100) and (111) surfaces through theoretical modeling of sputtering and annealing

The iron silicides formation during epitaxial film grown process on the (100) and (111) silicon surfaces were investigated using molecular dynamics (MD). The iron and silicon atom deposition rate and silicon substrate temperature influence on the formed iron silicide structure and stoichiometric composition were studied in detail. During the growth of iron silicide crystal structure significant diffusion of the substrate atoms into the forming BCC core occurs, this intensifies with the substrate temperature increase, and the ratio of substrate atoms inside the Fe3Si phase reaches nearly 12%. The BCC structure formation is less active on the (100) surface, and at the temperatures as low as 26 degrees C and 300 degrees C the iron silicide crystal phase does not form at all. However, with the temperature increase or the deposition rate decrease, the crystal structure formation processes occur more actively in both cases of (100) and (111) surfaces. Thus, the effect of the deposition rate decrease is identical to the temperature growth. It was shown that the formation of the structured B2 phase of iron silicide in buffer layer between the film and the substrate leads to the inhibition of the mutual diffusion of iron and silicon atoms.