Nanometer-scale Si/Au bilayer dots fabricated by self-assembly process through liquid phase epitaxy

Nanometer-scale Si/Au bilayer dots were fabricated on aflat Si surface. Au particles were produced by the gas-phase condensation method and deposited on the Si substrate. Post-thermal annealing in ultrahigh vacuum resulted in the formation of bilayer dots. The kinetics of bilayer formation was described as a process of self-assembly through liquid phase epitaxy. Then, one-directional diffusion was observed, although interdiffusion between the two elements commonly occurred at the Si/Au interface. The Au particles play the role of the transport medium. Namely, a few monolayers of the surface Si were dissolved into Au, formed SiAu alloy which was then regrown on the surface shape of dot with the Au particle on it.