The Formation of Cu₃Si from Cu/a-Si Multilayers

Abstract

The kinetics of the formation of Cu₃Si in Cu/a-Si diffusion couples have been investigated by means of differential scanning calorimetry and x-ray diffraction. Multilayered composites of average stoichiometry Cu₃Si were prepared by sputter deposition with individual layer thicknesses varying in different samples between 2 and 100 nm. We observed diffusion limited growth of Cu₃ Si upon annealing these diffusion couples below 500 K. Reaction constants were measured for a temperature range of 455 to 495 K for thicknesses of growing Cu₃Si between 2.6 and 80 nm. The temperature dependence of the reaction constant, k², was characterized as k² = k₀ exp(−E_a/k_bT) with activation energy, E_a = 1.0 eV/atom and pre-factor, k₀ = 1.9xs10^-3 cm²/s.