Interfacial reactions of 2-D periodic arrays of Ni metal dots on (0 0 1) Si

The fabrication of 2-D periodic arrays of nickel metal dots using polystyrene (PS) nanosphere lithography and the interfacial reactions of the Ni dot arrays on (0 0 1) Si substrates after different heat treatments have been investigated. The epitaxial NiSi2 was detected to start growing in samples after annealing at 300 °C. As the annealing temperature was increased to 350–800 °C, only epitaxial NiSi2 nanodot arrays were observed to form. The results revealed that the formation of epitaxial NiSi2 is more favorable for the Ni metal dot arrays samples. The shape of the epitaxial NiSi2 nanodot was found to be inverse pyramidal and the size of the silicide nanodots was measured to diminish with annealing temperature. Furthermore, amorphous SiOx nanowire arrays and single-crystalline Si nanowires were found to form in samples after annealing at 900 and 1100 °C, respectively. The results present the exciting prospect that other nanoscale metal silicide dot and nanowire arrays could be grown on the sub-100 nm pre-patterned Si substrates using the PS nanosphere lithography technique.