In order to synthesize a layer of narrow-gap indium antimonide (InSb) in the near-surface region of a Si single crystal, sequential high-dose implantation of Si with In+ and Sb+ ions with an energy of 30 keV and  a dose of 2×1016 cm–2 was carried out. Annealing of implanted Si:(In+Sb) layers in the liquid phase regime was carried out with a powerful pulsed (~100 ns) ion beam (C+/H+) with energy of 300 keV and pulse energy density of 1.0 J/cm2. Calculation of the total depth profile of the concentration of implanted In and Sb atoms taking into account ion sputtering showed their maximum concentration of 40 at.% at a depth of about 20 nm. Using the Rutherford backscattering of He+ ions, the segregation of impurity atoms to the Si surface as a result of pulsed annealing was detected. The spectra of X-ray diffraction in grazing beams and Raman light scattering indicate the formation of InSb phase with a tensile strain level of 0.6–0.7%. Using optical IR spectra, the electron concentration in the layer (2×1020 cm-3) due to the Sb donor impurity was estimated and the formation of an intense absorption band at 3.85 μm was shown. Photoresponse measurements on a diode mesa-structure at 300 K showed a shift in the photosensitivity edge to 1240 nm compared to a standard Si photodiode FD-24.