Structural properties of Fe ion implanted and ruby laser annealed Si layers

Abstract

The processes in the synthesis of iron silicide thin films (FeSi and FeSi2) on a single-crystal Si substrate implanted with different doses of Fe+ ions (D = 1015–2 × 1017 cm−2) and subjected to pulsed laser annealing (λ = 0.69 µm, τ = 80 ns, W = 0.6–1.4 J cm−2) are investigated. Using x-ray diffraction, transmission electron microscopy and Rutherford backscattering spectrometry, the structure and phase composition of the synthesized films and the depth profile of Fe atoms in the Si are studied. It is shown that laser annealing (W = 0.6–1.1 J cm−2) of high-dose implanted Si (D > 1017 cm−2) results in the formation of epitaxial iron monosilicide (FeSi) layers. Increasing the pulse energy up to 1.4 J cm−2 leads to a redistribution of Fe atoms in the Si and formation of a mixture of silicide phases (FeSi+FeSi2) with the cellular structure of a synthesized layer. In the case of low-dose implanted Si (D ∼ 1016 cm−2), the formation of cellular structures takes place at lower energy densities (W ∼ 0.8 J cm−2), with segregation of Fe atoms to the Si surface.

Phase transitions in erbium-doped silicon exposed to laser radiation

“…Diffusion into the material began to prevail over segregation onto the surface as the Er concentration increased. We observed similar redistribution of Fe in Si [8] during PLT.…”