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The structure of individual multi-wall carbon nanotubes exposed to irradiation by a argon ions and electron flux, as well as subsequent heat processing in an inert medium has been studied using transmission electron microscopy and x-ray photoelectron spectroscopy. It has been shown that irradiation with argon ions and electrons leads to the formation of defects in the structure of carbon nanotubes, changes in the interlayer distance in the walls of nanotubes, and the fixing of functional oxygen-containing groups on their surface. Annealing of pre-irradiated nanotubes in an inert atmosphere causes a partial restoration of the multi-wall carbon nanotube structure. At the same time, in the case of irradiation with argon ions, the nanotube structure is being recovered and the oxygen concentration decreases. In the case of electron irradiation after annealing, extended multi-vacancy defects occur, on which functional groups containing a double chemical bond of carbon and oxygen (C=O) are formed. Using calculations carried out within the framework of density functional theory, the coupling energy values and optimized geometry for various configurations of vacancy clusters in the graphene plane have been obtained.

Multilayer integrated porous membranes are obtained in a monolithic frame containing two types of porous silicon: macroporous silicon with pore diameters up to 10 μm and channel silicon with channel diameters from 100 to 300 nm. A laboratory technology is proposed for preparing macroporous/channel silicon two-layer structures with the use of high-resistance n-Si substrates (1 Ω cm). The pore-formation mechanism and its effect on the morphology of porous layers for electrolytes using formic acid and ammonium hydroxide are discussed.

The morphology, structure, and electrophysical characteristics of multiwall carbon nanotubes (MWCNTs), as affected by defects induced by ion bombardment, are studied using Raman spectroscopy and scanning and transmission electron microscopies. Annealing in an inert atmosphere results in partial recovery of the nanotube structure: the nanotube walls contain regions of recovered graphene structure and regions plagued with extended defects that result in corrugation of graphene layers comprising the walls of MWCNTs. These structural alterations result in a marked decrease in conductivity of the processed MWCNTs.

Changes in the local atomic and electronic structure and the chemical state of the surface of multiwalled carbon nanotubes (MWCNTs) irradiated with continuous and pulsed ion beams are studied using transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray absorption near-edge spectroscopy. It is demonstrated that changes in the structure and the chemical state of MWCNTs under continuous irradiation with argon ions are attributable to the radiation-induced defect formation. When a pulsed carbon–proton beam is used, thermal effects exert a considerable influence on the structure of carbon nanotubes. The obtained results suggest that continuous and pulsed ion beams are suitable for targeted functionalization of physical and chemical properties of MWCNTs.

Data on the distribution of iron in nitrogen-containing multiwall carbon nanotubes (N-MWCNTs) and changes in its chemical state and concentration under different parameters of irradiation by a pulsed ion beam are obtained by methods of transmission electron microscopy, X-ray photoelectron spectroscopy, and energy dispersion analysis. It is shown that the irradiation of N-MWCNTs with an energy density of 0.5 J/cm2 lead to the formation, on their lateral surfaces, of structures with a size of 2–10 nm, consisting of metallic iron encapsulated in a carbon shell. An increase in the energy density to 1–1.5 J/cm2 leads to a substantial removal of iron clusters from the tips of carbon nanotubes and a reduction in the amount of iron in the bulk of the N-MWCNT layer.

Using the methods of X-ray photoelectron (XPS) and X-ray absorption near edge structure (XANES) spectroscopies with synchrotron radiation, data on changes in the electronic structure and chemical composition of nitrogen-containing multiwalled carbon nanotubes (N-MWCNTs) upon their exposure to the radiation of argon ions with an energy of 5 keV are obtained. It is found that the exposure leads to an increase in the degree of defectiveness of the N-MWCNTs structure and to the carbon oxidation with formation of various oxygen-containing groups (C–OH, C=O/COOH, C–O–C/O–C–O, and CO3). The presence of carbon–oxygen bonds on the surface of carbon nanotubes is associated with the formation of radiation defects. It is shown that an increase in the fraction of nitrogen atoms present in the substituting configuration in the N-MWCNTs wall structure due to the irradiation does not give rise to an increase in the density of the occupied states near the Fermi level against the background of an increase in the degree of structure defectiveness, carbon oxidation, and a decrease in the total nitrogen concentration. The obtained results show that the irradiation of N-MWCNTs with argon ions allows one to successfully functionalize their surface.

The oxidation of mesoporous silicon in a double-layer “macroporous silicon–mesoporous silicon” structure is studied. The morphology and dielectric properties of the buried insulating layer are investigated using electron microscopy, ellipsometry, and electrical measurements. Specific defects (so-called spikes) are revealed between the oxidized macropore walls in macroporous silicon and the oxidation crossing fronts in mesoporous silicon. It is found that, at an initial porosity of mesoporous silicon of 60%, three-stage thermal oxidation leads to the formation of buried silicon-dioxide layers with an electric-field breakdown strength of Ebr ~ 104–105 V/cm. Multilayered “porous silicon-on-insulator” structures are shown to be promising for integrated chemical micro- and nanosensors.

The specific features of changes in the electronic structure of multi-walled carbon nanotubes (MWCNTs) due to the interaction with an amorphous tin oxide in the SnO x /MWCNT composite formed by magnetron sputtering have been investigated using X-ray spectroscopy. It has been shown that the formation of chemical bonds responsible for significant changes in the local and electronic structures of the outer layers of MWCNTs occurs at the boundaries of the “amorphous oxide/MWCNT” contacts. The vacuum annealing of the composite leads to the disturbance of the chemical interaction at interfaces of the composite and to a partial recovery of the local structure of the outer layers of MWCNTs. A decrease in the amount of oxygen in the tin oxide under vacuum annealing conditions causes an increase in the number of unpaired Sn 5s electrons, which, in turn, enhances the charge transfer through the interfaces in the composite and leads to a splitting of the π*-subsystem of the outer layers of MWCNTs.

The transformation of the structural phase state and the electronic structure of the SnO2 − x /MWCNT composite has been studied using X-ray spectroscopy and high-resolution transmission electron microscopy. It has been shown that the character of the interaction of the metal-oxide component of the composite with the array of carbon nanotubes depends on the structural state of tin oxide in globules of the metal-oxide component. In the initial composite with a large content of amorphous tin oxide, covalent functionalization of the MWCNT surface occurs. High-vacuum annealing results in the formation of a nanocrystalline structure in globules of the metal-oxide component and is accompanied by changes in the character of its interaction with carbon tubes.

The changes in the electronic structure and phase composition of porous silicon under action of pulsed ionic beams have been studied by X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge spectroscopy (XANES) using synchrotron radiation. The Si 2p and O 1s core photoemission spectra for different photoelectron collection angles, valence band photoemission spectra, and X-ray absorption near-edge fine structure spectrain the region of Si L2,3 edges of the initial and irradiated samples have been analyzed. It has been found that, as a result of the irradiation, a thin oxide film consisting predominantly of higher oxide SiO2 is formed on the porous silicon surface, which increases the energy gap of the silicon oxide. Such film exhibits passivation properties preventing the degradation of the composition and properties of porous silicon in contact with the environment.

The effect of pulsed ion irradiation and vacuum annealing on the ratio of sp2- and sp3-hybridized orbitals of carbon atoms in the layers of oriented multi-walled carbon nanotubes has been studied by analyzing the photoemission spectra of the C1s core level and the valence band of carbon, which were obtained using the equipment of the BESSY II Russian-German beamline of synchrotron radiation and a Riber analytical system. It has been shown that the ion irradiation leads to a significant decrease in the fraction of atoms with the sp3 hybridization of electrons. On the contrary, the annealing reduces the fraction of the sp3-component in the spectra of carbon. Typical features of the valence band of multi-walled carbon nanotubes in the annealed and irradiated states have been established.

The interaction mechanisms between NO2 molecules and the surface of por-Si/SnO x nanocomposites obtained by magnetron deposition and chemical vapor deposition (CVD) are studied by infrared absorption spectroscopy and electron paramagnetic resonance methods. The observed increase in the free carrier concentration in the por-Si/SnO x nanocomposite layers is explained by a change in the charge state of P b centers due to the formation of neutral “surface defect-adsorbed NO2 molecule” complexes with free carrier generation in the crystallite bulk. In the nanocomposite layers grown by the CVD method, the increase in the free hole concentration during NO2 adsorption is much less pronounced in comparison with the composite grown by magnetron deposition, which is caused by the competing interaction channel of NO2 molecules with electrically neutral P b centers.

The origin of the low-frequency band (250–300 cm−1) in the Raman spectra of multi-walled carbon nanotubes (MWCNTs) produced by the CVD method has been studied. The studies performed by Raman spectroscopy, transmission electron microscopy, Auger spectroscopy, and X-ray photoelectron spectroscopy after chemical and thermal treatments allow the assumption that this band belongs to radial vibrations of carbon atoms in internal walls of MWCNTs.

Nanocomposite layers based on multiwalled carbon nanotubes (MWCNTs) and non-stoichiometric tin oxide (SnO x ) have been grown by magnetron deposition and CVD methods. In the case of the CVD method, the study of the structure and phase composition of obtained nanocomposite layers has shown that a tin oxide “superlattice” is formed in the MWCNT layer volume, fixed by SnO x islands on the MWCNT surface. During magnetron deposition, the MWCNT surface is uniformly coated with tin oxide islands, which causes a change in properties of individual nanotubes. Electrical measurements have revealed the sensitivity of nanocomposite layers to (NO2)− molecule adsorption, which is qualitatively explained by a change in the conductivity of the semiconductor fraction of p-type MWCNTs.

The electrical characteristics and chemical reactant sensitivity of layers of heterogeneous nanocomposites based on porous silicon and nonstoichiometric tin oxide por-Si/SnO x , fabricated by the magnetron sputtering of tin with subsequent oxidation, are studied. It is shown that, in the nanocomposite layers, a system of distributed heterojunctions (Si/SnO x nanocrystals) forms, which determine the electrical characteristics of such structures. The sensitivity of test sensor structures based on por-Si/SnO x nanocomposites to NO2 is determined. A mechanism for the effect of the adsorption of NO2 molecules on the current-voltage characteristics of the por-Si(p)/SnO x (n) heterojunctions is suggested.

Two-phase nanocomposite layers based on porous silicon and nonstoichiometric tin oxide were fabricated by various methods. The structure, as well as elemental and phase composition, of the obtained nanocomposites were studied using transmission and scanning electron microscopy, Raman spectroscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy. The results obtained confirm the formation of nanocomposite layers with a thickness as large as 2 μm thick and SnO x stoichiometry coefficients x = 1.0–2.0. Significant tin diffusion into the porous silicon matrix with D eff ≈ 10−14 cm2 s−1 was observed upon annealing at 770 K. Test sensor structures based on por-Si/SnO x nanocomposite layers grown by magnetron deposition showed fairly high stability of properties and sensitivity to NO2.

The effect of ethanol vapor adsorption on the properties of porous silicon-based structures was studied by Raman scattering, infrared spectroscopy, and I–V characteristics. A decrease in the resistance of porous silicon layers and a simultaneous increase in the intensity of the band of infrared absorption caused by the presence of (OH)−…x(OH)− (x = 1, 2, …) groups upon exposure to ethanol vapor and vice versa in the case of degassing were detected. The observed effect is attributed to a change in the depletion region in por-Si skeleton elements due to the electrostatic interaction of (OH)− groups with positively charged surface defects. The effect of hydrogen-bonded Si-OH…OH-C2H5 centers on the increase in the silicon conductivity is discussed.

The method of atomic-force microscopy is used to study the morphology of the surface of porous silicon layers formed on the p-Si substrate and obtained by anodic etching in an electrolyte with addition of free halogens (bromine, iodine) and potassium halogenides (KCl, KI). It is established that the presence of halogens in the electrolyte is conducive to formation of large pores with the diameter as large as 150 nm. The mechanism of an increase in the pore sizes with involvement of halogens is related to an increase in the concentration of free holes due to formation of donor-acceptor pairs in the case of adsorption of halogens on the silicon surface.

The photoluminescence properties of type II GaAs/AlAs superlattices grown on the (311) surface are determined by their polarity. Previous HRTEM investigations demonstrated a corrugation (with height of 1 nm and period of 3.2 nm) of both GaAs/AlAs and AlAs/GaAs interfaces in samples grown on the (311)A surface. In the present study, a lateral periodicity of 3.2 nm is also revealed in HRTEM images of a superlattice grown on the (311)B surface and in their Fourier transforms. However, this periodicity is poorly pronounced, which is due to fuzzy corrugation and the presence of a long-wavelength (>10 nm) disorder. Photoluminescence spectra of the GaAs/AlAs superlattice on the (311)A surface are strongly polarized relative to the direction of interface corrugation, in contrast to the (311)B superlattice, in which the corrugation is weakly pronounced. It was found that the strong mixing between the Θ and X minima of the conduction band, occurring only in sublattices with strongly corrugated interfaces, allows generation of bright red luminescence at 650 nm up to room temperature. The distinctions revealed between the superlattices grown on the (311)A and (311)B surfaces confirm that it is precisely the interface corrugation, and not crystallographic orientation, that governs the optical properties of (311) superlattices.

Interaction of radiation defects with phosphorus atoms in silicon crystals subjected to electron irradiation and thermal treatments was studied under conditions of various degrees of supersaturation with respect to the equilibrium concentration of impurities and point defects. It is shown that, in the course of silicon irradiation, the electron-dose dependences of the phosphorus concentration at the lattice sites (Ps) level off (tend toward a constant value). This constant value is governed by the irradiation temperature. The stages of recovery of the concentration Ps as a result of heat treatments correlate with temperature intervals of dissociation of the vacancy complexes. The results indicate that there are two processes. One process involves the interaction of dopant atoms with silicon self-interstitials and the emergence of interstitial complexes; i.e., this process corresponds to the radiation-stimulated decomposition of a supersaturated solution of an impurity as a result of point-defect generation and ionization. The other process consists in the recombination of interstitial impurities with vacancies at sufficiently high temperatures or in the annihilation of vacancies released during heat treatments with interstitial atoms incorporated into composite defect complexes with the involvement of phosphorus atoms.

Using Raman scattering, it was ascertained that silicon nanocrystals with sizes exceeding 2 nm are formed in amorphous silicon films exposed to nanosecond ultraviolet laser radiation with energy densities ranging from 75 to 150 mJ/cm2; it is shown that these nanocrystals have sizes no smaller than 2 nm and have preferred (100) orientation along the normal to the film surface. In a system of mutually oriented Si nanocrystals, anisotropic behavior of the Raman scattering intensity was experimentally detected in various polarization configurations, which made it possible to determine the volume fraction of oriented nanocrystals. The orientational effect is presumably caused by both the macroscopic fields of elastic stresses in the film and the local fields of elastic stresses around the nanocrystals.

Phonon spectra of GaAs/AlAs superlattices (SLs) grown on (311)A, B and (001) surfaces were studied using Raman spectroscopy. The thickness of GaAs layers were varied from 1 to 10 monolayers (MLs); the thickness of AlAs barriers were 8 ML in the (311) direction. Different polarization geometries of Raman scattering were applied to study LO and TO modes. The splitting of TOx (atoms displace in the direction [01] perpendicular to the facets on the (311)A surface) and TOy (atoms displace in the [33] direction parallel to the facets) modes was observed for (311)A SLs. In the case of (311)B SLs no splitting was observed. The phonon anisotropy of (311)A SLs may be indirect evidence of anisotropic structure of quantum objects formed on the (311)A GaAs surface. In the Raman spectra of the SL containing GaAs submonolayers (SML) grown on a (2×4) reconstructed (100) surface, Raman peaks corresponding to additional lateral confinement of LO phonons were observed. The calculations of Raman spectra were carried out using the Born-von-Karman model (taking into account Coulomb interaction in the rigid-ion model) and the Wolkenstein bond polarizability model. According to the calculations, the interface structure strongly influences the Raman spectra of GaAs/AlAs heterostructures containing GaAs SML.

Studying GaAs/AlAs superlattices containing a quantum-well-wire array revealed photoluminescence polarization anisotropy for samples with GaAs layers less than 21 A thick. It was found that polarization for a thickness of more than 40 A was mainly due to valence band anisotropy, whereas polarization for a thickness of less than 21 A was equally attributable to both valence band anisotropy and anisotropy associated with interface corrugation. For a GaAs layer thickness of less than 21 A, a blueshift of the Γ electron-Γ heavy hole transition was observed. In this transition, the position of the peak of photoluminescence from the GaAs/AlAs (311)A superlattices containing a quantum-well-wire array is shifted toward higher energies compared to the (311)B and (100) superlattices containing no quantum-well wire with the same GaAs layer thickness. The conclusion was made that a blueshift is observed in GaAs/AlAs superlattices with GaAs layers less than 21 A thick and a red-shift is observed when the thickness is larger than 43 A.

The phonon-plasmon interaction in tunneling GaAs n /AlAs m superlattices (m=5and 6≥n≥0.6 monolayers) was studied by Raman scattering spectroscopy. The interaction of optical phonons localized in GaAs and AlAs layers with quasi-three-dimensional plasmons strengthens as the thickness of GaAs quantum wells decreases and the electronic states in the superlattices become delocalized due to tunneling. It is assumed that the plasmons also interact with the TO-like phonon modes localized in quantum islands or in thin ruffled layers.

GaAsn/AlAsm superlattices grown on the GaAs (311)A and (311)B surfaces by molecular-beam epitaxy were studied by Raman light scattering. The form of the Raman scattering tensor allowed the TO y and TO x modes to be separately observed using various scattering geometries (the y and x axes correspond to atomic displacements along and across facets formed on the (311)A surface, respectively). The TO1y and TO1x modes exhibited splitting in superlattices grown on a faceted GaAs(311)A surface. The degree of splitting increased for superlattices with an average GaAs layer thickness of 6 monoatomic layers and less. No splitting was observed for superlattices grown under the same conditions on the (311)B surface, which indicates that the splitting effect is probably due to the formation of GaAs quantum wires on the faceted (311)A surface.

Near-edge IR luminescence with peak emission at E = 1.084 eV has been studied in n- and p-type silicon samples with different contents of interstitial oxygen under excitation with a Nd: YAG laser diode. Thermal treatments of the samples demonstrated that the luminescence nearly completely disappears upon thermal treatments at T = 1050°C and is partly restored in two stages in subsequent thermal treatments in the temperature range 550–800°C. The temperature intervals of luminescence quenching and restoration (500–600 and 700–800°C) correlate with the temperature ranges of dissolution for shallow oxygen precipitates (1000°C) and the generation of oxygen-containing thermal defects, the so-called thermal donors of types I and II. The data obtained suggest that the electronic states related to thermal donors are traps for nonequilibrium carriers and the emptying of these traps contributes to the near-edge emission.

The use of Raman scattering in different polarization geometries makes it possible to observe the splitting of transverse optical (TO) phonon modes confined in GaAs/AlAs superlattices grown on faceted GaAs (311)A surfaces. The frequencies of TO modes with atomic displacements in the direction along the facets were observed to be higher than in the transverse one. Increased splitting, up to 3.5 cm − 1, was observed for (311)A superlattices when the average thickness of the GaAs layers was 6 monolayers or less. The splitting was absent in superlattices grown on (311)B surfaces under the same conditions. The effect of splitting is reputed to be caused by corrugation of GaAs/AlAs (311)A interfaces and formation of lateral superlattices or arrays of quantum wires, depending on the GaAs layer thickness.

The Raman spectra and current-voltage characteristics of porous silicon layers are studied before and after exposure to NO2. It is shown that spherical nanocrystallites with the diameter of approximately 6–8 nm are present in the samples’ structure. The effect of NO2 brings about a decrease in the resistance of porous Si by two-three orders of magnitude. An increase in the conductance of the structures at gas concentrations as high as 2000 ppm and a drastic decrease in this conductance if the concentration exceeds the above value are observed. This effect is explained in the context of the model that implies the formation of additional defects of the type of dangling silicon bonds at the Si/SiO2 interface as a result of oxidation of the porous silicon surface. These defects are traps for holes and reduce the increase in the hole concentration.

Anisotropy of Raman scattering is observed in the system of silicon nanocrystals inside amorphous films. The observed anisotropy is established to be the result of planar correlated orientation of nanocrystals which have (1 1 0) orientation in the normal direction. Preferred orientation is proposed to be due to the deformation contribution in the process of nanocrystals formation under nanosecond laser impact.

The efficiency of the introduction of donor centers in oxygen-containing Si by heat treatments at 450°C after preliminary hydrogenation in hydrogen plasma and irradiation with 60Co γ-ray photons was studied. It is shown that the highest rate of the donor-center introduction is observed in the samples that contain atomic hydrogen. Irradiation with 60Co γ-ray photons of Si with a layer preliminarily hydrogenated in hydrogen plasma leads to the release of atomic hydrogen from bound states. This makes the rate of the introduction of donor centers higher in subsequent heat treatments at 450°C.

The solid-phase crystallization process in thin amorphous silicon films on glass substrates was studied with application of excimer laser annealing (ELA) and rapid thermal annealing (RTA) for stimulation of nucleation. Use of ELA allowed us to create homogeneous polycrystalline silicon films on glass with grain sizes up to at temperatures below C. Use of RTA reduced the incubation time of nucleation from 100 to 6 h. The textured silicon films on glass with predominant orientation (110) and sizes of textured areas up to were manufactured using excimer laser stimulation of nucleation. The influence of the mechanical stress mechanism on grain orientation was suggested, and it was theoretically shown that internal stresses retard the nucleation process. The addition of deformation to the chemical potential difference was estimated for nucleation in amorphous silicon as 11.4 meV per nucleated atom.

In-depth distributions of PsV and CiPs complexes formed in the space-charge regions of Au/n-Si Schottky diodes irradiated with fast electrons in a special electrical regime have been investigated. In the course of the irradiation the diodes were periodically driven into the reverse-bias state with square-shaped voltage pulses of fixed amplitude alternating with the forward-current pulses at a 2 MHz frequency. Non-flat profiles of PsV concentration have been revealed by deep-level transient spectroscopy measurements, while the interstitial defects been revealed by deep-level transient spectroscopy were found to have a constant density. The result is regarded as strong evidence for the long-range (approximately 0.1-1 mu m) field-assisted drift of negatively charged vacancies (V-) across the depleted region. The diffusion length of V- evaluated from the drift model (about (3.8+or-0.4)*10-2 mu m for the float-zone silicon used with a phosphorus content of 5*1015 cm-3) was found to be consistent with the value expected from the theory of diffusion-limited reactions.

Application of implantation was demonstrated to be an effective method of mechanical stress relaxation in SOS structures. Experimental results were obtained concerning stress relaxation in SOS structures under post-implantation thermal treatments. Proposed models of defect formation and reconstruction near the Si-Al 2 O 3 interface in conditions of high non-equilibrium concentration of point defects and impurities are discussed. The stress relaxation is explained by interaction of vacancy defects with compressive stresses and the probable creation of a dislocation net in the case of annealing after boron implantation. Theoretical consideration of stress distribution in SOS structures with compensating defects is presented. Evidence of accumulation of vacancy defects at the Si-Al 2 O 3 interface was experimentally obtained and theoretically proved.

Raman investigation of oxygen precipitation in silicon was carried out taking into consideration the stress environment of precipitates and interaction with interstitial atoms. Influence of oxygen precipitates on efficiency of stacking faults and dislocation loops formation was observed. Stresses that evolved in the precipitation process during thermal treatments were detected by Raman measurements. Strong correlation of measured stress distribution with defects distribution was obtained. A physical model was proposed incorporating stress profiles due to precipitate formation with emitted interstitial atoms, interaction of the precipitate with interstitial atoms in a deformation mechanism and growth of the precipitate surrounded by interstitial-like dislocation loops with elimination of the stress. On the basis of the suggested approach stresses were modelled for the case of a nonuniform distribution of precipitates. Comparison with Raman data provided information on stress tensors around the precipitate.

Concentration profiles of the centers with shallow and deep levels and the distribution of generation lifetimes after fast neutron irradiation of n- and p-type silicon, hydrogenized in the hydrogen plasma of a HF discharge and in boiling distilled water, are determined by means of measuring of capacitance—voltage (C—V) and current—voltage (I—V) characteristics and DLTS spectra in Schottky diodes. The passivation effects are observed both for point-like radiation defects and for radiation defects in disordered regions (DR) due to the regeneration of mobile hydrogen atoms from bonded forms (pairs of shallow acceptor—hydrogen, H2, and others) under the neutron irradiation. The decrease of the degradation rate of the generation lifetimes is observed in hydrogenated silicon layers under irradiation. It is found that the efficiency of passivation of the radiation defects is greater in n-type than in p-type silicon, and depending on technique and duration of hydrogenation, the efficiency of passivation drops down with increasing neutron dose. [Russian Text Ignored].

Etude de la distribution de l'or et de sa redistribution sous irradiation d'electrons d'energie E=3,5 MeV dans des couches epitaxiales de silicium. On presente les profils de concentration apres la creation des jonctions p.n.

Gold distribution in SiO2Si structures after diffusion and its redistribution under irradiation by high-energy electrons are studied by DLTS and SIMS methods. It is shown that the concentration of substitutional gold increases at radiation doses of 1013 to 1014 cm−2, which is due to the presence of a previously inactive interstitial component AuI and its dissolution in vacancies. A radiation dose increase results in radiation-induced gettering of gold by the SiO2Si interface with subsequent penetration of gold into SiO2. The state of the SiO2Si interface affects the behaviour of gold at irradiation. [Russian Text Ignore]

Both, changes in the states of oxygen and carbon impurities in silicon due to heat treatments within a temperature range from 600 to 1000 °C and the efficiencies of radiation defect formation under electron irradiation in as-grown and heat-treated materials are investigated using IR-spectroscopy, DLTS, and Hall-effect measurements. In phosphorus-doped silicon the removal rate of free electrons is found to decrease as a result of preliminary heat at 900°C. Comparison with the results obtained on accumulation of deep level centers suggests that the above effect is caused by a decrease of the production rate of compensating acceptor defects with the levels in the lower half of the forbidden gap or by an increase of the efficiencies of sinks for silicon self-interstitials. interaction of which with phosphorus donors causes electrical compensation of the material after irradiation. [Russian Text Ignored.]

The accumulation of structural defects in neutron-irradiated silicon with different impurity contents is studied by the method of IR spectroscopy. It is shown that the annihilation of vacancies and interstitial silicon atoms on oxygen is essential in the accumulation of radiation defects during this kind of irradiation. Vacancy-oxygen complexes are preferably formed near the disorder regions (DR). This may be explained on the basis of concepts of radiation-accelerated diffusion of oxygen to the DR. The nature of elastic stresses in DR containing silicon crystals at different stages of irradiation is discussed. The estimations of elastic stresses made on the basis of data of optical measurements give ≈ 104 to 105 N/cm2. It is shown that the quantities of one-phonon and near-edge absorption are determined by the available gradients of distribution of defects arising during the neutron irradiation. [Russian Text Ignored].

The method of IR-absorption is used to study the increase of efficiency of the introduction of vacancy-oxygen (VO) complexes in silicon at electron irradiation with the growth of the concentration of boron and carbon impurities. The dose dependences of the change of concentrations of substitutional carbon, interstitial oxygen, and of CO complexes are obtained. On the basis of results gained a quantitative model is proposed of radiation defect formation in silicon containing sinks for intrinsic interstitial atoms (boron, carbon, and others). The model involves the conception on annihilation of vacancies (V) and interstitial atoms of silicon (I) on defect centers. A numerical calculation of the kinetics of defect formation and of the change of impurity states in silicon under irradiation is made. The kinetic parameters of the processes are found from a comparison of the calculation with experimental data. The values obtained of reaction constants show the possibility of prediction of radiation defects accumulation in silicon with different impurity content. [Russian Text Ignore]