Ion-beam-induced epitaxy and interfacial segregation of Au in amorphous silicon

The segregation and diffusion of Au are examined during ion-beam-induced solid phase epitaxial crystallization of Au-implanted amorphous silicon layers. Epitaxy was induced at temperatures as low as 220 °C by irradiation with 1.5 MeV Ar ions. At these temperatures Au is segregated to form a narrow layer at the moving crystal/amorphous interface. The size of the segregated layer depends on the velocity of the interface compared to the Au diffusivity in amorphous Si. The growth rate for ion-beam-induced epitaxy is found to be independent of Au concentration and near-complete epitaxial crystallization of the amorphous layers can be achieved, even for Au concentrations ∼2 at. %.