On the nanometer-scale solid-state reactions at thin-film Ni/amorphous SiC and Co/amorphous SiC interfaces

Abstract

Solid-state interfacial reactions between self-supporting thin (50, 100, and 200 Å) films of Ni and Co, and amorphous (a) films of SiC, Si and C were investigated in the 300–1000 °C temperature range. The metastable solubility of C (from SiC) in Ni and Co after short annealings was calculated from the metal lattice expansion after accounting for the effect of Si. A maximum of ∼7 at. % C dissolves in (Ni) at ∼300 °C, a value close to the maximum solubility of C in rapidly quenched Ni-C alloys. In contrast, a lack of change in the Co lattice parameter after reactions with either SiC, Si, or C indicates negligible dissolution of C prior to silicide nucleation. The first silicides in metal/a-SiC reactions (Ni31Si12, and Co2Si) are more metal-rich than in metal/a-Si reactions.