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

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 120 keV Fe+ ions to a fluence of 4.0 x 10(17) cm(-2) at cryogenic temperature (120 K). 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 similar to 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. (c) 2005 American Institute of Physics.