On the synthesis of nanoscale phases of metal silicides in the near-surface region of silicon and the study of their electronic structures by passing light

Abstract

The band gap E_g of nanocrystalline phases NaSi₂ and CoSi₂ synthesized on the surface and in the near-surface region of silicon by ion implantation in combination with annealing is determined by measuring the intensity of light at different frequencies, passing through the test samples, and by using ultraviolet photoelectron spectroscopy. The nanoscale phases MeSi₂ (Me = Na, Co) on the surface of silicon are obtained by the implantation of Me ions with the energy E₀ = 1 keV; and in the near-surface region (at a depth of 15–16 nm), by the implantation of ions with E₀ = 15 keV. Postimplantation annealing is mainly carried out by heating. It is shown that MeSi₂ nanocrystalline phases both on the surface and in the near-surface layer are crystallized in the cubic lattice. It is found that E_g of the nanocrystalline metal-silicide phases, depending on their size, can range from 0.6 to 1 eV.