The structure, diffusion and phase formation in Mo/Si multilayers with stressed Mo layers

Processes of diffusion and silicide formation in stressed multilayers of Mo/Si, as a result of their isothermal annealing, were studied in this paper by methods of cross-sectional transmission electron microscopy and X-ray diffraction techniques. It was found that reaction with growth of molybdenum disilicide of reduced density takes place at Mo-on-MoSi2 interfaces up to formation of ∼ 7 nm thick layers, due to annealing treatment within 350-400 deg. C temperature range. Silicon atoms were found to be the dominating diffusive components. As a result of Si atoms' diffusion from Si layer, sublayers of a somewhat lower density are being formed at MoSi2-on-Si interfaces. Growth of molybdenum disilicide is accompanied by reduction of multilayer period. Activation energy of diffusion process (phase formation) makes up ∼ 2.2 eV. Influence of compressive stresses (that exist in Mo layers) on process of phase formation, both in as-deposited and in annealed samples, is discussed in this paper