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 E
 0 = 1 keV; and in the near-surface region (at a depth of 15–16 nm), by the implantation of ions with E
 0 = 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.

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

The topography, composition, and electronic and crystal structures of the surface of SiO2 films fabricated by the implantation of O2+ ions in Si (111) with subsequent annealing are investigated. It is established that at high ion implantation doses (D ≥ 6 × 1016 cm−2), continuous homogeneous polycrystalline SiO2 films form, while at relatively low doses (D = 8 × 1015−4 × 1016 cm−2), SiO2 films with regularly arranged Si nano-areas with a density of 1010–1011 cm−2 form.

Energy spectra of SiO2 nanofilms formed on a silicon surface by ion implantation

The effect of preliminary low-energy (~1 keV) and low-dose (~1012–1014 cm–2) ion bombardment on the initial stages of growth of Si films on a CaF2/Si surface is investigated. Ordered nanocrystal phases (thickness less than 5–6 monolayers) and homogeneous epitaxial nanofilms (thickness more than 8–10 monolayers) of silicon are shown to be formed after annealing.

On the creation of ordered nuclei by ion bombardment for obtaining nanoscale si structures on the surface of CaF2 films

The effect of Ar+-ion bombardment on the surface composition and structure of CoSi2/Si nano-films is studied. It is demonstrated that ion bombardment leads to the decomposition of CoSi2 and enrichment of the film surface with Si atoms. After heating at T = 850–900 K, the Si-CoSi2-Si nanofilm system forms.

Effect of Ar+-ion bombardment on the composition and structure of the surface of CoSi2/Si(111) nanofilms

The influence of the bombardment by the Ar + , Ba + and Na + ions and the subsequent annealing on composition and electron structure of a surface of the CaF 2 /Si (1 1 1) films is studied. The energy band diagram of the epitaxial nanofilm systems of the Ca–CaF 2 –Si type is constructed. Optimum regimes of ion implantation and annealing for the production of three-componental nanodimensional structures of the Ca 1− X Ме X F 2 type are determined and parameters of their energy bands are estimated.

Investigation of change of the composition and structure of the CaF2/Si films surface at the low-energy bombardment

It is established that ion implantation in combination with annealing makes it possible to produce regularly arranged nanocrystalline phases and continuous films of metal silicides in the surface region of Si. It is shown that silicide nanocrystals and nanofilms crystallize in the cubic lattice. A model of a Si surface with silicide nanocrystals is developed.

Structure and electronic properties of nanoscale phases and nanofilms of metal silicides produced by ion implantation in combination with annealing

A review of the experimental results on the study of the Si, GaAs, and CaF2 surface layers that are created using the low-energy ion implantation is presented. Optical and electron spectroscopy and microscopy are employed in the experiments.

Electron spectroscopy of the nanostructures created in Si, GaAs, and CaF 2 surface layers using low-energy ion implantation

The composition and structure of nanodimensional Ga1 – xNa
 x
 As phases produced by implantation of Na+ ions into the near-surface area of GaAs have been studied by Auger electron spectroscopy and fast electron diffraction. It has been found that the thickness of the ternary epitaxial layer is 10–12 nm for ion energy E0 = 20 keV. The composition of the three-layer nanosystems is GaAs–Ga0.5Na0.5As–GaAs.

Composition and Structure of Ga 1 - x Na x As Nanolayers Produced near the GaAs Surface by Na + Implantation

Auger electron spectroscopy and secondary-ion mass spectrometry are used to study the compositions of uncontrolled impurity atoms, their chemical composition, and the atomic distribution profiles at the Al-Si interface. Low concentrations (<0.1%) of impurity C, O, N, Ti, Fe, and other atoms are detected in Al. An analysis of the chemical shifts of the Auger peaks of metal atoms shows that compounds of the AlO and Al2O3 types form at the Al-Si interface.

Kh. Kh. Boltaev

Papers

Structure and electronic properties of nanoscale phases and nanofilms of metal silicides produced by ion implantation in combination with annealing

Electron spectroscopy of the nanostructures created in Si, GaAs, and CaF 2 surface layers using low-energy ion implantation

Composition and Structure of Ga 1 - x Na x As Nanolayers Produced near the GaAs Surface by Na + Implantation

Composition of uncontrolled impurities and their chemical states and depth profiles at the Al-Si interface

Study of the Composition of Uncontrolled Impurities and the Profiles of Their Distribution at the Ni–CdS Interface