Nucleation and growth of epitaxial silicide in nanowire of silicon

When two nanowires cross each other, they form a point contact. Point contact reaction between a nano metal wire and a nano Si wire has been studied by using ultra-high vacuum and high resolution transmission electron microscopy. Axel epitaxial growth of nano silicides of NiSi and CoSi₂ in nanowires of Si has been observed. The nucleation stage and stepwise growth stage of the reactive epitaxial growth of nano silicide on nano Si have been measured. A repeating event of homogeneous nucleation has been found, which enables us to estimate the number of molecules in a critical nucleus to be about 10 using the Zeldovich factor. A comparison to heterogeneous nucleation will be made. The nucleation-controlled or supply-controlled growth mode of point contact reactions is different from the well-known diffusion-controlled and interfacial-reaction-controlled modes of growth in thin film and bulk samples.