Fabrication of periodic nickel silicide nanodot arrays using nanosphere lithography

The interfacial reactions of the 2D-ordered nickel metal nanodots that were prepared by polystyrene nanosphere lithography (NSL) on Si substrates after different heat treatments have been investigated. Epitaxial NiSi2 nanodot arrays were found to form at a temperature as low as 350 °C. The results indicated that the growth of epitaxial NiSi2 is more favorable for the Ni metal dot array samples. The sizes of these epitaxial NiSi2 nanodots in samples annealed at 350-800 °C are in the range of 84-110 nm. The shape of the epitaxial NiSi2 nanodot was found to be pyramidal. Furthermore, for the samples annealed at 900 °C, amorphous SiOx nanowires were found to grow on individual nickel silicide nanoparticles. The diameters of these nanowires are in the range of 15-20 nm. As the size of metal nanodot can be adjusted by tuning the diameter of the polystyrene (PS) spheres, the NSL technique promises to be an effective patterning method without complex lithography.