Thermally induced transition metal contamination of silicide Schottky barriers on silicon AIP Conf.The solid state reaction between a Ni ͑7 at. % Au͒ film and a Si substrate at temperatures ranging from 250 to 800°C is examined by scanning electron microscopy, x-ray diffraction, and Rutherford backscattering spectrometry. Compared to the usual features for thin film reaction of Ni with Si, we observed the following. ͑i͒ The simultaneous growth of Ni 2 Si and NiSi, and the growth of NiSi at the expense of both Ni 2 Si and Ni. This is related to Au accumulation in the metal layer. ͑ii͒ Au precipitation at 300°C followed by the dissolution of the clusters thus created above the Au-Si eutectic temperature ͑370°C͒. ͑iii͒ A decrease of the temperature of formation of NiSi 2 and the appearance of thickness oscillations that are characteristic of nucleation. These different effects are interpreted by taking into account the metallurgy of the system: segregation of Au in the Ni film, Au solubility in the different silicides, change in surface and interface energies, and chemical interactions with Si.

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Formation of epitaxial Si1−yCy substitutional alloy layers on monocrystalline silicon surfaces with y≊1 at. % is reported. The preparation method was carbon ion implantation, followed by KrF excimer laser annealing. Results of Rutherford backscattering (RBS), secondary ion mass spectrometry (SIMS) and infrared absorption analyses are compared. The authors concluded that, up to ∼1 at. % carbon content, the dominant process is nonequilibrium trapping of carbon in substitutional lattice sites upon fast resolidification. Above this concentration the complex carbon redistribution processes are influenced by silicon carbide precipitation in the melt and segregation effects in the near-surface region.

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