The solid state reaction between metallic thin films with a silicon substrate still needs to be investigated in the ultra-thin film regime. X-ray diffraction and substrate curvature measurements were combined during in situ synchrotron experiments to follow the reaction kinetics and the evolution of stresses during phase formation. Pd/Si is a model system; a unique phase forms: Pd2Si. The results show that the Zhang-d'Heurle model explains the stress evolution during annealing, which comes from the competition of two mechanisms: the development of compressive stress due to the formation of a new phase and the stress relaxation of already formed silicides. However, transmission electron microscopy and pole figures demonstrate different textures of this phase depending on the substrate orientation. On Si(111), Pd2Si is in epitaxy, whereas on Si (001), the phase has a texture that evolves during annealing. This evolution may be activated by a diffusional creep mechanism then by plastic deformation. The study of Ni ultra-thin films shows that there is a critical thickness (< 6 nm) below which the phase sequence and texture are changed. Using different techniques, it has been shown that from 200 °C, the NiSi phase grows as a homogeneous and continuous layer. Then increasing temperature, the texture and morphology of NiSi change and NiSi coexists with NiSi2. They exhibit a morphology in the form of islands that penetrate into the substrate or in the form of elongated platelets.
