Structures with strained and unstrained silicon layers were studied by ultrasoft X−ray emission spectroscopy and X−ray absorption near edge structure spectroscopy with the use of synchrotron radiation techniques the SOI (silicon−on−insulator). Analysis of X−ray data has shown a noticeable transformation of the electron energy spectrum and local partial density of states distribution in valence and conduc- tion bands in the strained silicon layer of the SOI structure. USXES Si L2,3 spectra analysis revealed a decrease of the distance between the L′2v и L1v points in the valence band of the strained silicon layer as well as a shift of the first two maxima of the XANES first derivation spectra to the higher energies with respect to conduction band bottom Ec. At the same time the X−ray standing waves of synchrotron radiation (λ ~ 12−20 nm) are formed in the silicon−on−insulator structure with and

without strains of the silicon layer. Moreover the synchrotron radiation grazing angle θ changing by 2° leads to a change of the electromagnetic field phase to the opposite. 

P–type thermoelectric Bi0,5Sb1,5Te3 powders were obtained by the melt spinning technique (extremely rapid quenching from the liquid state) and their structural and dimensional characteristics were characterized. The crystallographic group and the lattice parameters of the powders correspond to those for Bi0,5Sb1,5Te3 crystallized in equilibrium conditions which suggests the identity of the crystal structure. The powders were compacted by vacuum hot pressing and spark plasma sintering. We found that the partial axial texture [001] directed along the axis of pressure application could be formed during the compacting of the powders. Temperature dependences of the thermoelectric characteristics of the compacted material were measured in a direction perpendicular to the pressure application axis in the 100—700 K range. It is demonstrated that the compacted samples possess low thermal conductivity while retaining the Seebeck coefficient and the electrical conductivity values comparable to crystallized material; therefore ZT reaches 1,05—1,15 in the 330—350 K range which indicates high prospects of applying these technologies. 

Development and search for new advanced materials of the lanthanum gallium silicate group with unique thermal properties is of great importance for the development of acoustoelectronics based on volume and surface acoustic waves. The processes of surface acoustic wave excitation and propagation in the La3Ga5.3Ta0.5Al0.2O14 crystal was studied using a double−crystal X−ray diffractometer with a BESSY II synchrotron radiation source. The X−ray diffraction spectra of acoustically modulated crystals were used to measure the surface acoustic wave velocity and power flow angles in different acoustic cuts of the La3Ga5.3Ta0.5Al0.2O14 crystal. 

Ferrite−ceramic materials are widely used in electronics. The most widely used is Mn—Zn−ferrite due to its high permeability. However, Mn—Zn−ferrites obtained by the standard process flow (ITS) have the texture along the pressing axis which significantly reduces their permeability and causes anisotropic properties. The difference in the magnetic permeability along and perpendicular to the pressing axis reaches 10—20 % due to the texture. The texture of the raw blanks is caused by lamellar ferrite particles [1] and the orientation of the [111] crystallographic axes along the compression axis. During sintering the degree of texture increases due to the preferential growth of pressing−oriented particles at the expense of non−oriented ones. As a result, an easy magnetization axis formed in the sintered ferrite which coincides with the compression axis. Most sizes of ferrite products are manufactured in such a way that the magnetic field lines in their operation do not coincide with the compression axis (ring, P−and R−core), which significantly reduces their operating parameters. To reduce the texture in this study we used a short process flow diagram including only one heat treatment i.e. sintering of the blanks pressed directly from the mixture of the raw ferrite oxide particles that are oriented but slightly when pressed. We show that isotropic Mn—Zn−ferrite with the desired magnetic properties at CCC can be obtained using bismuth oxide additives and a complex composition of binder during compaction instead conventionally used polyvinyl alcohol. 

The existing methods of diagnosis of solid surfaces in ion− plasma processes have been analyzed. We found that the most efficient method of estimating surface condition, determining the transition of the etching process from one layer to another and determining the end of the etching process is the registration of ion−electronic emission during ion−beam etching. Results on secondary electron current for ion beam etching of various semiconductors have been reported. We show the experimental setup and describe the electric circuit for the detection of secondary electrons. An experimental study has been carried out to determine the dependence of secondary electron current on the band gap Eg and the height of the potential barrier (electron affinity) χ of Ge, Si, GaAs, GaP and SiC semiconductor materials. We found no clearly expressed dependence of integral signal of ion−electronic emission on Eg and χ. We show that under the conditions of ion beam etching under the influence of the surface potential the electric field penetrates in the semiconductor volume, leading to a shift in the energy levels of electrons in the surface layer and a change in the secondary electron current due to the appearance of autoelectronic emission. We found that the signal of ion−electronic emission in n−type silicon is higher than in p−type silicon. A model of ion−electronic emission from the surface of semiconductors is presented for the conditions of ion−beam etching, consisting of: emission with the participation of conductivity band electrons, emission due to the direct transition of electrons in the ion – atom system, and autoelectronic emission under the influence of surface potential. 

The suggested model simulates the structural evolution of the SiOm (m < 2 ) layer with a thickness of the order of 3—30 nm and the formation of Si nanoclusters in that layer during thermal annealing at temperatures of 900—1200 °C. The model does not take into account the crystallinity or amorphous structure of the nanocluster. The 3D cellular automaton model implemented by means of SoftCAM software (CA) on 3D cubic grid with a cell scale of 0.54 nm is synchronous, does not use Margolus’s block neighborhood and is open to the incorporation of ab initio calculations for SixOy clusters. The state of the CA cell is determined by three variables (x, y, z), taking on 0,1,2 , ..., 255 and corresponding to the number of atoms of silicon and oxygen and the arbitrary “free volume” in a cell and the fourth variable δ, taking on 0, 1, 2 and corresponding to cells belonging to nanoclusters, SiOx matrix or the interface between them. The local transition rules are determined from the following considerations: 1) for each cell, the scalar “free energy” is calculated similar to the thermodynamic potentials, as it depends only on the state of the cell; 2) the “free energy” consists of three parts: the internal U(x, y), the elastic G(z) and the surface E(δ); 3) the matter exchange between cells is determined by probabilities depending on the difference between the “free energy” by the Fermi— Dirac relation. The model traces the total number of nanoclusters, their average size and the average distance between them. The simulation results are consistent with published experimental data. 

We consider the properties of gas sensitive films of poly- acrylonitrile (PAN) and copper−containing PAN in the framework of QSPR (Quantitative Structure—Property Relationship). We propose linear regression models to predict the resistance, the thickness of the studied films and the gas sensitivity coefficients of PAN and copper− containing PAN films based on descriptors that take into account the technological and structural parameters of the material forming the gas sensitive layer of the sensor. 

The Ti/Al/Ni/Au metallization system which is widely used in the technology of GaN based devices has a very important disadvantage: after annealing in nitrogen atmosphere for 30 sec. at temperature 850 оС it has rough surface with 300 nm hillocks. This creates troubles for lithographic processes. The aim of this work is to investigate the mechanism that generates the roughness of this surface and ways to minimize this disadvantage. We have studied the formation of rough surface in Ti/Al/Ni and Ti/Al/Ni/Au multilayer metallization systems. The resistivity of the metallization sheet increases with an increase of annealing temperature. This can be attributed to the mutual diffusion of metals and their active interaction with the formation of intermetallic phases. X−ray analysis proved the appearance of the following basic intermetallic phases: NiTi, Al3Ti, и Ni2Al3 in the metallization systems. After annealing the surface of metallization system Ti/Al/Ni becomes rougher; however, large hemispherical convexes (as in the Ti/Al/Ni/ Au metallization system) are not generated. Thus, the hypothesis of balling−up of molten Al−Ni alloy on the surface of metallization system Ti/Al/Ni has not been confirmed. 

To decrease the amount of Au–Al liquid phase that causes the rough surface of Ti/Al/Ni/Au metallization we reduced the thickness of the Au layer to 50 nm. At this Au layer thickness the surface morphology of metallization became much better: roughness reduced from 300 nm to 80 nm and the surface became specular. 

Tin, iron and nickel oxides were prepared in micro porous silicon from sols. The morphology of the samples was studied using atomic force microscopy. The сross−sections of porous silicon were investigated using scanning electron microscopy. The electrical properties were investigated by impedance spectroscopy in a changing environment and temperature of gas detection reagents. The dependencies of real and imaginary components of the complex impedance were constructed in the semi−logarithmic coordinates. The method of complex plane was used for processing the experimental impedance data. Hodographs of impedance were analyzed using programs writteng in the LabVIEW environment. The experimental impedance spectroscopy data were interpreted in terms of «equivalent electrical circuit». Сonstant phase element was used to describe the resistive− capacitive properties of nanocomposite materials in the equivalent electrical circuit. The characteristic charge accumulation time in air and in the presence of reducing gases was calculated. The sensitivity to reducing gases for the real and imaginary components of the complex impedance was calculated using two methods at 300 °C in the frequency range from 1 Hz to 500 kHz. The sensor characteristics of metal oxide films grown on single−crystal substrates, porous silicon and glass substrates were compared. 

The electronic structure and geometry of metal−carbon nanocomposites based on the pyrolyzed poliacrylonitril (PPAN) with Cu, Si, Fe, Co, Ni atoms using the DFT method have been theoretically studied. The effect of nitrogen on the stability of PPAN and its conductivity has been determined. The electrophysical properties and structure of metal nanocomposites have been studied using the XFA method. The composites have been produced by IR heating. We suggest that metal−carbon nanocomposites form due to the special processing of the (PAN−MeR) samples. Metal nanoparticles are regularly dispersed in the nanocristalline matrix of PPAN. The conductivity of this metal−carbon nanocomposites has an activation character and varies from10−1 to 103 Om/sm depending on synthesis temperature (T = 600—900 °С). The results of theoretical and experimental research are in good agreement. 

Comprehensive studies of the structure and electronic properties of defects occurring on the connection boundary of disarranged n−type Si(001) wafers have been made by the methods of transmission electron microscopy, deep level transient spectroscopy (DLTS) and photoluminescence. The main revealed defects are two types of dislocation structure: orthogonal dislocation network composed of two screw dislocation families and zigzag mixed dislocations. The dislocation structures observed are sources of intense luminescence whose spectra are appreciably different from the standard dislocation luminescence spectra at all the investigated misfit angles of the Si bonded wafers. We show that an increase of the misfit angle results in a strong transformation of the dislocation luminescence spectra consisting in changes of the form of the spectra and a decrease in the integral luminescence intensity. In the samples in question the DLTS method revealed the presence of deep centers the concentration of which increased with increasing of twist misorientation of bonded wafers. It has been established that the deep centers are related to the dislocation structures observed by means of transmission electron microscopy. 

The structural state of GexSi1−x films grown on Si substrates with the vicinal orientation (1 1 13) has been studied. The (1 1 13) orientation has been obtained by rotating the singular plane (001) around the [11−0] axis. The x parameter of GexSi1−x films in different samples ranged from 0.083 to 0.268. Triclinic distortions arising in film crystal lattice have been analyzed using our technique developed for the determination of epitaxial layer structural parameters based on the X−ray diffractometry data. It has been established that during the epitaxial process the film lattice turns around the direction of surface steps due to the introduction of misfit dislocations into the interface. Dislocations with Burgers vector a/2<110> which is not parallel to the interface create an analog of a tilt boundary. The turning angle value ψ is proportional to the misfit dislocation density. This phenomenon is associated with a decrease of the interface symmetry that leads to a change in the efficiency of stress relieving by dislocations belonging to different families. The influence of these families on the low−angle boundary formation is considered. Experimental values of the ψ angle and shear strain for the [13 13 2−] and [1−10] directions lying in the interface (1 1 13) have been defined. A comparison of the experimental and calculated values of ψ for the [13 13 2−] direction is provided.