Fabrication and characterization of periodic arrays of epitaxial Ni-silicide nanocontacts on (1 1 0)Si

In this study, we report on the fabrication and characterization of periodic Ni and Ni-silicide nanocontact arrays on (1 1 0)Si substrates. From transmission electron microscopy and selected-area electron diffraction analysis, it is found that the epitaxial NiSi ₂ is the first and the only silicide phase formed in the nanoscale Ni contact/(1 1 0)Si sample after annealing at a temperature as low as 300 °C, demonstrating that the nanoscale Ni contact is more favorable for the epitaxial growth of NiSi ₂ phase on (1 1 0)Si. The orientation relationship between the epitaxial NiSi ₂ nanocontacts and the (1 1 0)Si substrate is identified as [1 1 0]NiSi ₂ //[1 1 0]Si and (1¯11¯)NiSi ₂ //(1¯11¯)Si. For the samples annealed at higher temperatures, all the epitaxial NiSi ₂ nanocontacts formed on (1 1 0)Si are anisotropic in shape and elongated along the crystallographic 11¯0 directions. The observed results can be attributed to the higher surface area to volume ratio of Ni nanocontacts and the faster growth rate along the 〈1 1 0〉 directions than along other directions. The size and periodicity of the nanocontacts can be readily controlled by adjusting the diameter of the colloidal nanosphere template. The self-assembled approach proposed here will provide the capability to fabricate other highly-ordered metal silicide nanocontact arrays and may offer potential applications in constructing silicide-based nanodevices.