Structural characterization of oxidized allotaxially grown CoSi2 layers by x-ray scattering

Abstract

A series of buried CoSi 2 layers prepared by a modified molecular beam epitaxy process ͑allotaxy͒ and a subsequent wet-oxidation process was investigated by x-ray scattering. The oxidation time which determines the depth in which the CoSi 2 layers are located within the Si substrates has been varied during the preparation. The electron density profiles and the structure of the interfaces were extracted from specular reflectivity and diffuse scattering measurements. Crystal truncation rod investigations yielded the structure on an atomic level ͑crystalline quality͒. It turns out that the roughness of the CoSi 2 layers increases drastically with increasing oxidation time, i.e., with increasing depth of the buried layers. Furthermore, the x-ray data reveal that the oxidation growth process is diffusion limited.

Controlled growth of extended arrays of CoSi2 hexagonal nanoplatelets buried in Si(001), Si(011) and Si(111) wafers

“…We can understand that the diffusion of Co atoms only occurs along {111} planes in the three studied Si wafers because the observed CoSi 2 {111}/Si{111} interfaces exhibit a surface energy lower than those corresponding to the interfaces with other Si crystallographic planes. 19 The formation of the CoSi 2 island epitaxially grown on the surface of Si single crystals has been previously reported, [20][21][22][23] but the formation of such islands forming endotaxially grown nanoplatelets by diffusion of Co atoms into Si along Si{111} planes, regardless of the orientation of the silicon crystal, was -to our knowledge -not previously reported. Moreover, Mahato et al 23 observed the spontaneous change of shape of epitaxial CoSi 2 islands on Si(100) while treated at 600 1C in UHV, this effect leading to the formation of CoSi 2 endotaxial nanowires.…”

Morphology and interdiffusion behavior of evaporated metal films on crystalline diindenoperylene thin films

“…⌬␣ is about twice the rocking width of the DIP͑001͒ reflection (0.013°). 35 The cross-sectional TEM images for samples A1-A4 as grown show large differences in the interfacial morphology depending on the preparation conditions ͑Fig. 3͒.…”

Contrast variation by anomalous X-ray scattering applied to investigation of the interface morphology in a giant magnetoresistance Fe/Cr/Fe trilayer

“…At higher incident angles, the specular reflected intensity in our experiment became comparable with, or even less than, the diffuse scattering photon intensity owing to the scattering from 'in-plane' roughness. There are methods (Kaendler et al, 2000) to separate the diffuse scattering from the specular reflectivity resulting in a 'true specular reflectivity' but, as already discussed (Prokert et al, 2003;Schlomka et al, 1995), the fitting of the 'true specular reflectivity' alone can give misleading results, especially in cases where the intensity due to diffuse scattering is comparable with the intensity due to specular reflectivity. This is the reason why we fitted simultaneously the diffuse and specularly scattering intensities.…”