Structural, Optical, and Photoelectric Properties of Silicon Implanted with Indium and Antimony Ions and Subjected to Pulsed Annealing

Abstract

Si single crystal was sequentially implanted with high doses (2∙1016 cm^-2) of In⁺ and Sb⁺ ions with an energy of 30 keV in order to synthesize a layer of narrow-gap indium antimonide (InSb) in its near-surface region. Implanted Si:(In + Sb) layers in the liquid phase were annealed with a powerful pulsed (~100 ns) ion beam (C⁺/H⁺) with an energy of 300 keV and a 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 ~20 nm. Segregation of impurity atoms to the Si surface because of pulsed annealing was detected using the Rutherford backscattering of He⁺ ions. X-ray diffraction spectra in grazing beams and Raman light scattering indicated an InSb phase with a tensile strain level of 0.6–0.7% formed. The electron concentration in the layer (2∙1020 cm^-3) due to the Sb donor impurity was estimated using optical IR spectra. An intense absorption band at 3.85 μm was shown to form. Photoresponse measurements on a diode mesa-structure at 300 K showed a shift in the photosensitivity edge to 1240 nm as compared to a standard FD-24 Si photodiode.