The formation of structures of nickel silicides on Si have been studied by the use of glancing angle X-ray diffraction, MeV4He+ backscattering, reflection electron diffraction and replica electron microscopy. By reacting evaporated Ni films with Si wafers in the temperature range of 200 to 800°C, we have found three Ni silicides. The phase Ni2Si starts to form at 200°C at the Si-Ni interface. Around 350°C, the phase NiSi grows from the Si-Ni2Si interface. The NiSi is stable in the temperature range of 350 to 750°C and above that it transforms abruptly to NiSi2. The disilicide grows epitaxially on (111), (110) and (100) surfaces of Si.

Implanted noble gas atoms of Xe have been used as diffusion markers in the growth study of three silicides: Ni2Si, VSi2, and TiSi2. Backscattering of MeV He has been used to determine the displacement of the markers. We found that while Si atoms predominate the diffusion in VSi2 and TiSi2, Ni atoms are the faster moving species in Ni2Si.

The diffusion of As implanted in thermally grown SiO2 was studied at temperatures in the range 1000°–1200°C using N2 and O2 as ambients. Concentrations were between 3×1015 normaland 3.5×1016 As+ ions cm−2 . Energies of 60 and 340 keV were used. Because of As loss due to evaporation, significant quantitative data could only be obtained for deep implants. N2‐normalannealed samples exhibit low diffusion rates at high concentrations (above the middle of the 1019 cm−3 range). Larger diffusion rates are observed at lower concentrations. In the samples treated in O2 , the opposite concentration dependence of the diffusivity is observed. The shape of the profiles suggests that in both cases a high and a low concentration phase exists. A model is presented assuming that in O2 a fully oxidized structure and in N2 an oxygen deficient network is obtained as a first step in the annealing process. There are indications that the ambient also affects the diffusion rate during further high temperature treatment of these structures, probably through the concentration of oxygen vacancies.

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The reaction rate of vacuum-evaporated films of V of the order of I 000 A thick is investigated by MeV He backscattering spectrometry. On substrates of single-crystal Si and for anneal times up to several hours in the temperature range 570--650 ·c, VSi 2 is formed at a linear rate in time. The activation energy of the process is 1.7±0.2 eV. The presence of oxygen in amounts of 10% can significantly decelerate the reaction. On substrates of Si0 2 in the temperature range 730--820 ·c and anneal times of several hours or less, V 3 Si is formed at a square-root rate in time. The activation energy of this process is 2.0±0.2 eV.