Structural characterisation of erbium silicide thin films on an Si(111) substrate

Atomic models for the ErSi2/Si(111) interface

“…The calculated images were compared to the available experimental HREM images (some of which have been presented in Ref. [7]). The investigation favored the validity of two of the above models, the models I and X.…”

“…The two letters in the parenthesis denote that, in the same layer, both types of the available sites are occupied by Si atoms. Superstructures of this basic structure have also been reported [5,7,12,13]. They arise after ordering of vacant sites on the Si sublattice, leading to a composition of ErSi 2-x (x ≤ 0.33).…”

“…Indeed, from the electron diffraction patterns, as well from HREM images [7], it is concluded that the silicide film is slightly strained to allow for a perfect match between the two structures. Thus, the interface models can be constructed considering zero mismatch and absence of misfit dislocations.…”

“…The high resolution electron microscopy (HREM) characterisation of all these samples was reported in ref. [7]. The silicide was found to grow epitaxially on the Si substrate.…”

“…Furthermore they can be grown relatively easily on a Si(111) substrate, in an epitaxial way, since they present a low lattice mismatch (1-2%). Several growth techniques have been applied, especially for the system ErSi 2 /Si(111), which has been the most extensively studied [1][2][3][4][5][6][7]. Recently the growth of thin films or nanostructures of ErSi 2 on Si(100) has also been reported [8][9][10][11].…”