Thermal and kinetic analyses of silicide formation at nanostructured Si/Ni interface

Abstract

The problem of the manifestation of nanostructures properties that are not typical for similar macrosystems is still relevant. First of all, this concerns the stability of the thermodynamic properties of nanomaterials, which determines the operational reliability of devices based on them. In this paper, the influence of the nanostructured Si/Ni interface on the mechanism of silicide formation is studied. For this purpose, nickel/porous silicon nanocomposites have been electrochemically synthesized and analyzed using the scanning electron microscopy and the phase X-ray diffraction analysis. The solid-state interaction during heating the nanocomposites has been investigated using differential scanning calorimetry. The evolution of phase composition in the temperature range 25–500 °C has been studied. The temperature characteristics of silicide formation processes have been estimated. Kinetic analysis of the solid-state interaction has been performed using the isoconversional Ozawa–Flynn–Wall method. The dependence of effective activation energy on conversion has been calculated from the calorimetric data. The mechanism of silicide formation in the nickel/porous silicon nanocomposite is shown to be significantly different from the bulk Ni–Si diffusion couple. At the same time, it has similarities with, but also some differences from, the silicide formation in thin-film Ni–Si systems and individual Si nanowires. Methodical aspects of the characterization of the thermal behavior of nanocomposites taking into account the nanorelief of the Si–Ni interphase boundary are discussed.