Diffusion in intermetallic compounds with the CaF2 structure: A marker study of the formation of NiSi2 thin films

Abstract

A xenon marker was implanted into a thin film of NiSi initially formed on its silicon substrate by the reaction of this substrate with a thin film of nickel. During the subsequent transformation of NiSi into NiSi2 at about 800 °C, the displacement of the xenon marker towards the free surface of the film indicates that nickel constitutes the main diffusive species for the growth of NiSi2. This is compared with the previously published knowledge about Ni2Si, NiSi, and the silicides of cobalt.

Modification effect of Ni–38wt.%Si on Al–12wt.%Si alloy

“…Ni-38 wt.%Si is composed of NiSi 2 and NiSi. NiSi 2 usually adopts a (cubic) CaF 2 crystal structure with lattice parameter a = 0.5395 nm, and composed of eight body-centered cubes adjacent to one another with all the corner sites occupied by silicon atoms [22,23]. The structure of NiSi was studied by the powder method by Borén [24] who described this compound as cubic (a = 0.4437 nm) of the FeSi type.…”

High-resolution transmission electron microscopy of silicide formation and morphology development of Ni/Si and Ni/Si1−xGex

“…By heating quickly to 900°C, a temperature at which NiSi is not stable, NiSi 2 is free to nucleate at random locations on a clean Ni/Si interface and grow by fast Ni diffusion through the NiSi 2 lattice via a vacancy mechanism. 17 The NiSi 2 adopts the cubic-CaF 2 structure in which each Ca 2ϩ ion is surrounded by eight Fions at the corners of a cube, and each F -ion by four Ca 2ϩ ions at the corners of a regular tetrahedron. Thus, NiSi 2 is composed of an octet of body-centered cubes in which the shared vertices are occupied by silicon atoms.…”

Structure and oxidation resistance of plasma sprayed Ni–Si coatings on carbon steel

“…and the Si substrates has also been observed during oxidation around 750℃ [10,11]. Therefore, the phase transformation of the Ni-Si coatings during oxidation is summarized as follows:…”