Linear growth kinetics of nanometric silicides in Co/amorphous-Si and Co/CoSi/amorphous-Si thin films

Abstract

Evolution of the reaction zone on the nanoscale has been studied in bi-and multilayered Co/a-Si as well as in trilayered Co/a-CoSi/a-Si and Co/CoSi/a-Si thin film diffusion couples. The kinetics of the phase boundary movement during solid state reaction has been followed with special interest of the initial stage of the diffusion, i.e. effects happening on the nanoscale ͑short time, short distance͒. The interfacial reactions have been investigated in situ by synchrotron radiation. The formed phases were also characterized by transmission electron microscopy and resistance measurements. The effect of phase nucleation and shift of phase boundaries have been separated in order to determine the "pure" growth kinetics of the crystalline CoSi and Co 2 Si product phases at the very early stages. Deviations have been found from the traditional diffusion controlled parabolic phase growth. Computer simulations based on a kinetic mean field model illustrated that the diffusion asymmetry ͑large difference in diffusion coefficients of the materials in contact͒ may offer a plausible explanations for this.

Metamorphic mineral reactions: Porphyroblast, corona and symplectite growth

“…As may be expected from the above considerations, layer growth is found to follow a linear rate law only as long as the layers are thin with thicknesses on the order of several tens of nanometres (Cserhati et al, 2008;Gö tze et al, 2014). If layer thickness is of magnitude l mm or more, parabolic growth is generally observed.…”

“…The effect of additional dissipative processes on layer growth rates, position of the Kirkendall plane and compositions of solution phases are well understood theoretically and quantitative models accounting for these effects have been presented. At present, the experimental evidence of systematic deviations from local equilibrium at reaction interfaces or from parabolic growth are scarce (Cserhati et al, 2008;Gö tze et al, 2014;Abart et al, 2016). This does not mean, however, that these effects can be ignored generally.…”

The transition from linear to-parabolic growth of Cu3Si phase in Cu/a-Si system

“…The investigation of different specimen geometries, especially thin layer interdiffusion couples/multilayers started to question the generality of these rules. New examples of linear kinetics were found in carefully prepared specimens [13][14][15][16]. Upon reviewing older literature (e.g.…”

Nanoresolution interface studies in thin films by synchrotron x‐ray diffraction and by using x‐ray waveguide structure

“… Abstract In the last years we performed several measurements with synchrotron radiation of several facilities to reveal interesting interface phenomena on the nanoscale. We used both x‐ray diffraction1, 2 (XRD) and spectrometry techniques. In this paper, we briefly summarize the results obtained from diffraction measurements, which lead us to our recent grazing incidence x‐ray fluorescence analysis (GIXRF) and extended x‐ray absorption fine structure (EXAFS) experiments. We show how a combination of experimental methods of GIXRF analysis and EXAFS spectroscopy in fluorescence detection with x‐ray standing waves (XSW) technique was applied for the depth profiling of a‐Si/Co/a‐Si layers with nanometer resolution to monitor the growth of CoSi intermetallic phase.…”

“…In the last years we performed several measurements with synchrotron radiation of several facilities to reveal interesting interface phenomena on the nanoscale. We used both x‐ray diffraction1, 2 (XRD) and spectrometry techniques. In this paper, we briefly summarize the results obtained from diffraction measurements, which lead us to our recent grazing incidence x‐ray fluorescence analysis (GIXRF) and extended x‐ray absorption fine structure (EXAFS) experiments.…”