Transmission electron microscopy study on ion-beam-synthesized amorphous Fe–Si thin layers

Abstract

Ion-beam-synthesized amorphous Fe–Si thin layers have been characterized using transmission electron microscopy (TEM) in combination with imaging plate techniques. Si single crystals with a (111) orientation were irradiated with 120keV Fe+ ions to a fluence of 4.0×1017cm−2 at cryogenic temperature (120K). Cross-sectional TEM observations indicated the formation of an amorphous bilayer on the topmost layer of the Si substrate. It was found that the upper layer is an amorphous Fe–Si with the composition, in terms of atomic ratio, of Fe∕Si ∼1∕2, while the lower one is an amorphous Si. Atomic pair-distribution functions extracted from microbeam electron diffraction patterns revealed that the nature of short-range order in amorphous Fe–Si thin layer can be well described by the atomic arrangements of crystalline iron silicides.