#### Results in Journal Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering: 315

##### (searched for: journal_id:(725533))
Page of 7
Articles per Page
by
Show export options
Select all
S. S. Kormilitsina, E. V. Molodtsova, S. N. Knyzev, R. Yu. Kozlov, D. A. Zavrazhin, E. V. Zharikova, Yu. V. Syrov
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 24; https://doi.org/10.17073/1609-3577-2021-1-48-56

Abstract:
The method of plane-transverse bending was used to measure the strength of thin single-crystal plates of undoped InSb with a crystallographic orientation of (100). It was found that the strength of the plates (thickness ≤ 800 μm) depends on their processing. Using a full processing cycle (grinding and chemical polishing) allows to increase the strength of InSb plates by 2 times (from 3.0 to 6.4 kg/mm2). It is shown that the dependence of strength on processing for wafers with (100) orientation is similar to this dependence for wafers (111), while the strength of wafers (111) is 2 times higher. The contact profilometry method was used to measure the roughness of thin plates, which also passed successive processing steps. It was found that during a full cycle of processing, the roughness of InSb plates decreases (R a from 0.6 to 0.04 μm), leading to a general smoothing of the surface roughness. The strength and roughness of the (100) InSb and GaAs wafers are compared. It was found that the strength of GaAs cut wafers is 2 times higher than the strength of InSb cut wafers and slightly increases after a full cycle of their processing. It was shown that the roughness of GaAs and InSb plates after a full cycle of surface treatment is significantly reduced: 10 times for InSb due to overall surface leveling and 3 times for GaAs (R z from 2.4 to 0.8 μm) due to a decrease in the peak component. Conducting a full cycle of processing InSb plates can increase their strength by removing broken layers by sequential operations and reducing the risk of mechanical damage.
, A. I. Ivanova, Gr. S. Shishkov, A. A. Martyanov
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 24; https://doi.org/10.17073/1609-3577-2021-1-40-47

Abstract:
In this paper, we compare the structure and dielectric properties of the samples of barium titanate ceramics that have been sintered at temperatures of 1100, 1150, 1200, 1250 and 1350 °C and dielectric characteristics of the samples of barium titanate (80 vol.%) — barium ferrite (20 vol.%). It is shown that only samples sintered at the temperature of 1250 and 1350 °C have polarization sufficient for the existence of the piezoelectric effect. For the same samples, the pyroelectric coefficient and reversal polarization significantly exceed those for samples sintered at lower temperatures. Analysis of the samples structure confirmed the dependence of the dielectric properties of the barium titanate ceramics on the grain size and, as a consequence, on the sintering temperature. Based on the studies carried out, the optimal temperature (1250 °С) for obtaining composite samples of barium titanate (80 vol.%) — barium ferrite (20 vol.%) was selected. The temperature dependence of the dielectric constant for the composite samples based on barium ferrite — barium titanate with a sintering temperature of 1250 °C is similar to the dependence for the BaTiO3 ceramic samples sintered at 1350 °C. At room temperatures, the permittivity of the composite samples is also significantly higher than that of the barium titanate ceramic samples obtained at the same sintering temperatures. The addition of barium ferrite to the barium titanate not only increased the permittivity of the composite, but also led to a diffusing of the ferroelectric phase transition and a shift in the temperature of the maximum of the dielectric constant by 10 degrees towards high temperatures.
A. A. Mololkin, , , R. R. Fahrtdinov
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 24; https://doi.org/10.17073/1609-3577-2021-1-34-39

Abstract:
Lithium niobate and lithium tantalate are among the most important and most widely used materials in acousto-optics and acoustoelectronics. These materials have high values of piezoelectric constants, which makes it possible to use these materials as actuators; however, their use is limited by the thermal instability of a lithium niobate crystal and the low Curie temperature (T C) of a lithium tantalate crystal. LiNb(1-x)TaxO3 crystals have to overcome the aforementioned limitations of individual compounds. Crystals LiNb0.5Ta0.5O3 were grown by the Czochralski method, of good quality. Comparative studies of the features of high-temperature single domainization of LiNb0.5Ta0.5O3 crystals have been carried out. The main differences in the technological regimes for single-domainization of congruent LiNb0.5Ta0.5O3 crystals from congruent LiNbO3 crystals are demonstrated. The parameters of high-temperature electrodiffusion processing LiNb0.5Ta0.5O3 crystals are presented, which make it possible to obtain single-domain crystals for further study of their physical properties.
T. G. Yugova, A. G. Belov, V. E. Kanevskii, E. I. Kladova, S. N. Knyazev
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 24; https://doi.org/10.17073/1609-3577-2021-1-27-33

Abstract:
A theoretical model has been developed that allows one to determine free electron density in n-GaAs from the characteristic points on far-infrared reflection spectra. It was shown that, in this case, it is necessary to take into account the plasmon-phonon coupling (otherwise, the electron density is overestimated). The calculated dependence of electron density, Nopt, on the characteristic wave number, ν+, which is described by a second degree polynomial, has been obtained.Twenty-five tellurium-doped gallium arsenide samples were used to measure the electron density in two ways: according to traditional four-contact Hall method (Van der Pauw method) and using the optical method we developed (measurements were carried out at room temperature). Based on the experimental results, the dependence was constructed of the electron density values obtained from the Hall data, N Hall, on the electron density obtained by the optical method, N opt. It is shown that this dependence is described by linear function. It is established that the data of optical and electrophysical measurements coincide if the electron density is N eq = 1.07 ⋅ 1018 cm-3, for lower values of the Hall density N Hall < N opt, and for large values NHall > Nopt. A qualitative model is proposed to explain the results. It has been suggested that tellurium atoms bind to vacancies of arsenic into complexes, as a result of which the electron density decreases. On the surface of the crystal, the concentration of arsenic vacancies is lower and, therefore, the condition N opt > N Hall should be satisfied. As the doping level increases, more and more tellurium atoms remain electrically active, so electron density in the volume begins to prevail over the surface one. However, with a further increase in the doping level, the ratio N Hall/N opt again decreases, tending to unity. This, probably, is due to the fact that the rate of decomposition of the complexes “tellurium atom + arsenic vacancy” decreases with increasing doping level.
A. V. Leonov, V. N. Murashev, D. N. Ivanov, V. D. Kirilov
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 24; https://doi.org/10.17073/1609-3577-2021-1-57-62

Abstract:
The influence of the coupling effect on the parameters of field Hall elements based on thin-film MOS transistors has been studied. Analysis of the development of today’s microelectronics shows the necessity of developing the element base for high performance sensors based on silicon technologies. One way to significantly improve the performance of sensing elements including magnetic field sensors is the use of thin-film transistors on the basis of silicon on insulator (SOI) structures. It has been shown that field Hall sensors (FHS) may become the basis of high-performance magnetic field sensors employing the coupling effect occurring in the double gate vertical topology of these sensing elements. Electrophysical studies of FHS have been conducted for different gate bias and power supply modes. The results show that the coupling effect between the gates occurs in FHS if the thickness of the working layer between the gates is 200 nm. This effect leads to an increase in the effective carrier mobility and hence an increase in the magnetic sensitivity of the material. Thus field Hall elements based on thin-film transistors fabricated using silicon technologies provide for a substantial increase in the magnetic sensitivity of the elements and allow their application in highly reliable magnetic field sensors.
V. N. Jarkin, O. A. Kisarin, T. V. Kritskaya
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 24; https://doi.org/10.17073/1609-3577-2021-1-5-26

Abstract:
Novel technical solutions and ideas for increasing the yield of solar and semiconductor grade polycrystalline silicon processes have been analyzed. The predominant polycrystalline silicon technology is currently still the Siemens process including the conversion of technical grade silicon (synthesized by carbon-thermal reduction of quartzites) to trichlorosilane followed by rectification and hydrogen reduction. The cost of product silicon can be cut down by reducing the trichlorosilane synthesis costs through process and equipment improvement. Advantages, drawbacks and production cost reduction methods have been considered with respect to four common trichlorosilane synthesis processes: hydrogen chloride exposure of technical grade silicon (direct chlorination, DC), homogeneous hydration of tetrachlorosilane (conversion), tetrachlorosilane and hydrogen exposure of silicon (hydro chlorination silicon, HC), and catalyzed tetrachlorosilane and dichlorosilane reaction (redistribution of anti-disproportioning reaction). These processes remain in use and are permanently improved. Catalytic processes play an important role on silicon surface, and understanding their mechanisms can help find novel applications and obtain new results. It has been noted that indispensable components of various equipment and process designs are recycling steps and combined processes including active distillation. They provide for the most complete utilization of raw trichlorosilane, increase the process yield and cut down silicon cost
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 24; https://doi.org/10.17073/1609-3577-2021-1-63-64

Abstract:
Review on the paper Wuzong Zhou, Reversed Crystal Growth. Crystals. 2019; 9(1): 7 (16 pp). https://doi.org/10.3390/cryst9010007
, K. I. Volovich, S. A. Denisov, Yu. S. Ionenkov,
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-3-241-247

Abstract:
This article discusses a methodology for assessing the effectiveness of a high-performance research platform. The assessment is carried out for the example of the "Informatika" Center for Collective Use (CCU) established at the Federal Research Center of the Institute of Management of the Russian Academy of Sciences, for solving new materials synthesis problems. The main objective of the "Informatika" Center for Collective Use is to conduct research using the software and hardware of the data center of the FRC IU RAS, including for the benefit of third-party organizations and research teams. The general characteristics of the "Informatika" Center for Collective Use are presented, including the main characteristics of its scientific equipment, work organization and capabilities. The hybrid high-performance computing cluster of the FRC CSC RAS (HHPCC) is part of the data center of the FRC IU RAS and also part of the “Informatika” Center for Collective Use. HHPCC provides computing resources in the form of cloud services as software (SaaS) and platform (PaaS) services. With the aid of special technologies, scientific services are delivered to researchers in the form of subject-oriented applications. Based on the analysis of the structure and operation principles of the Informatika Center, key performance indicators of the Center have been developed taking into account its specific tasks in order to characterize its various activity aspects (development, activities and performance). CCU efficiency evaluation implies calculation, on the basis of the developed indicators, of overall (generalized) indicators that characterize the CCU operation efficiency in various areas. An integral indicator is also calculated showing the overall CCU efficiency. To develop the overall performance indicators and the integral performance indicator, it is suggested to use the methods of weighted average and analysis of hierarchies. The procedure of determining partial performance indicators has been considered. Specific features of the choice of CCU performance indicators for solving new materials synthesis problems have been identified that characterize computing complex capabilities in the creation of a virtualization environment (peak performance of a computing system, real performance of a computing system on specialized tests, equipment loading with applied tasks and program code efficiency).
A. P. Marin, U. A. Marina, V. A. Vorob`ev, R. V. Pigulev
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-3-213-221

Abstract:
The paper presents the results of a study of the luminescent properties of calcium gallate activated by trivalent rare earth ions Yb3+ and Er3+. IR luminescence spectra of samples with a single activator Ca1‑ хYbxGa2O4,Ca1‑ хErxGa2O4 were studied when excited by radiation sources with a wavelength of 940 and 790 nm, respectively. The dependence of the luminescence intensity of samples on the concentration of rare earth ions is obtained. When the two-activator composition of Ca1‑ х‑yYbxEryGa2O4 is excited by a semiconductor laser diode with a wavelength of 940 nm, IR luminescence is registered in the regions of 980-1100 nm and 1450-1670 nm. The radiation in these bands corresponds to electronic transitions in Yb3+ and Er3+ ions, respectively. For a luminescence band with a maximum at a wavelength of 1540 nm, the excitation spectra were measured, the maximum intensity is at the wavelengths: 930, 941, 970, 980 nm. The dependence of the IR luminescence intensity of a solid solution of Ca1‑ х‑yYbxEryGa2O4 on the concentration of Er3+ ions was studied. With an increase in the concentration of Er3+ ions in the luminescence spectra, there is a redistribution in the intensity of the bands belonging to Yb3+ and Er3+ ions, which indicates the presence of energy transfer processes between these ions. The kinetics of IR luminescence attenuation was studied for series with one and two activators: Ca1‑ хYbxGa2O4,Ca1‑ хErxGa2O4, Ca1‑ х‑yYbxEryGa2O4. It is established that the luminescence attenuation occurs mainly according to the exponential law, which indicates the predominance of the intracenter luminescence mechanism in the studied structures. Based on the analysis of the excitation and luminescence spectra of experimental samples, conclusions are made about the interaction of Yb3+ and Er3+ activator ions in the crystal lattice of calcium gallate.
V. Yu. Zheleznov, T. V. Malinskiy, S. I. Mikolutskiy, V. E. Rogalin, , Yu. V. Khomich, V. A. Yamshchikov, ,
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-3-203-212

Abstract:
Методами оптической профилометрии, сканирующей электронной и зондовой микроскопии исследована модификация полированной поверхности {111} монокристаллического германия (n-тип проводимости, удельное сопротивление 47 Ом · см) в результате воздействия сфокусированным частотно-импульсным излучением наносекундного ультрафиолетового Nd : YaG лазера. Выявлено, что порог плазмообразования с образованием кратера на поверхности возникает при плотности энергии лазерного излучения Е ~ 1,2÷1,3 Дж/см2. При неподвижном положении образца при Е ~ 0,1 Дж/см2 возникали необратимые повреждения поверхности. При сканировании поверхности излучением при Е ~ 0,50÷1,15 Дж/см2, в отсутствии заметных следов кратерообразования, наблюдалось образование ямок травления с правильной трехгранной формой, концентрация которых составляла (3—5) ⋅ 105 см-2. Фигуры напоминают дислокационные ямки травления, получаемые селективным химическим травлением.Выявление дислокаций происходило путем абляции в результате воздействия лазерного излучения. Центрами зарождения абляции являются дислокации, выходящие на поверхность кристалла. Поперечный размер ямок травления составил ~5—10 мкм, и их перекрытие привело к чередующейся картине трехгранных пирамид, образованных плоскостями {111}. Наблюдали скругленные грани и вершины пирамид, высота профиля фигур составила ∼1—2 мкм. Линейные размеры ямок свидетельствуют о быстром протекании процесса. Исходя из суммарного времени воздействия излучения на поверхность ∼200 нc установлена скорость формирования плоских граней в ямках, которая составляет ∼0,1—0,3 м/с, что на несколько порядков превышает скорость формирования таких же граней при росте кристалла. Глубина поверхностного слоя, в котором происходило формирование структуры, составляла ∼15 мкм.
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-3-186-195

Abstract:
Artificial neural networks play an important role in the modern world. Their main field of application is the tasks of recognition and processing of images, speech, as well as robotics and unmanned systems. The use of neural networks is associated with high computational costs. In part, it was this fact that held back their progress, and only with the advent of high-performance computing systems did the active development of this area begin. Nevertheless, the issue of speeding up the work of neural network algorithms is still relevant. One of the promising directions is the creation of analog implementations of artificial neural networks, since analog calculations are performed orders of magnitude faster than digital ones. The memristor acts as the basic element on which such systems are built. A memristor is a resistance, the conductivity of which depends on the total charge passed through it. Combining them into a matrix (crossbar) allows one layer of artificial synapses to be implemented at the hardware level. Traditionally, the STDP method based on Hebb’s rule has been used as an analog learning method. In this work, we are modeling a two-layer fully connected network with one layer of synapses. The memristive effect can manifest itself in different substances (mainly in different oxides), so it is important to understand how the characteristics of memristors will affect the parameters of the neural network. Two oxides are considered: titanium oxide (TiO2) and hafnium oxide (HfO2). For each oxide, a parametric identification of the corresponding mathematical model is performed to best fit the experimental data. The neural network is tuned depending on the oxide used and the process of training it to recognize five patterns is simulated.
I. N. Ganiev, S. E. Otajonov, M. Mahmudov, M. M. Mahmadizida, V. D. Abulkhaev
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-3-222-228

Abstract:
It is known that high purity aluminum with a minimum content of impurities is widely used in electronic technology for the manufacture of conductive paths in integrated circuits. Hence the development of new compositions of alloys based on such a metal is a very urgent task. One of the promising alloys based on such a metal is alloy AK1M2 (Al + 1 % Si + 2 % Cu). This alloy was accepted by us as a model alloy and subjected to modification by alkaline earth metals.Heat capacity is the most important characteristic of substances and by its variation with temperature one can determine the type of phase transformation, the Debye temperature, the energy of formation of vacancies, the coefficient of electronic heat capacity, and other properties. In the present work, the heat capacity of the AK1M2 alloy with alkaline earth metals was determined in the “cooling” mode from the known heat capacity of a reference sample from copper. For which, by processing the curves of the cooling rate of samples from the alloy AK1M2 with alkaline earth metals and the standard, polynomials were obtained which describe their cooling rates. Further, by experimentally found values of the cooling rates of the standard and samples from alloys, knowing their masses, the polynomials of the temperature dependence of the heat capacity of the alloys and the standard were established, which are described by a four-term equation. Using the integrals of the specific heat, the models of temperature dependence of the change in enthalpy, entropy and Gibbs energy were established.The dependences obtained show that with an increase in temperature, the heat capacity, enthalpy, and entropy of alloys increase, and the values of Gibbs energy decrease. At the same time, additives of alkaline earth metals do not significantly reduce the heat capacity, enthalpy and entropy of the original alloy AK1M2 and increase the value of Gibbs energy. During the transition from alloys with calcium with barium, the heat capacity of the alloys decreases, which correlates with the heat capacity of pure alkaline earth metals within the subgroup.
N. A. Kulchitskiy, A. V. Naumov, V. V. Startsev
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-3-167-176

Abstract:
Analysis of current GaAs and related device market initiated in a number of earlier works has been continued. Binary semiconductor GaAs compound is a conventional MW electronics material. Until recently GaAs based HF ICs for mobile phones were among the most rapidly growing segments of GaAs market. However the GaAs market development trend is changing. Photonics and TeraHertz engineering are becoming the new world GaAs market drivers. This means that the current emphasize of GaAs single crystal technologies will shift toward vertical directional crystallization of “optoelectronic quality” crystals. In the medium and longer terms the world GaAs wafer and epitaxial structure markets will continue growing. In the shorter term we all will have to take into account COVID epidemic consequences. Still the GaAs market is closely related to Smartphone market novelties. Quite probably after a long growth period the GaAs market will keep on shrinking for the second consecutive year: GaAs production may decline by 11–12 % in 2020. Assuming that the epidemic will be somehow taken under control in 2021 the overall Smartphone production can probably be expected to grow starting from 2021.Currently the Russian market of semiconductor compounds for photonics and electronic components (GaAs etc.) is but moderate and in predictable terms is not expected to achieve a level that is required for the emergence of a competitive domestic manufacturer, even though all importation replacement programs are accomplished. Meanwhile there is understanding that developing an advanced electronic components industry in Russia requires larger production of source materials.
V. A. Tedzhetov, A. V. Podkopaev, A. A. Sysoev
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-3-177-185

Abstract:
The development of high energy physics and medicine has raised the necessity of heavy stintillating materials with a large total gamma quantum absorption cross-section, high quantum output and fast response. Cerium doped lutetium silicate Lu2SiO5 : Ce3+ (LSO) has high density, large effective atomic number and high conversion efficiency. In this work we have reported optical absorption spectroscopy and photoluminescence data for LSO single crystals grown using the modified Musatov method. The absorption spectra show the fundamental intrinsic absorption edge of Lu2SiO5 at ~200 nm and four extrinsic absorption bands of Ce3+ activator near 250—375 nm. The band gap is 6.19 to 6.29 eV depending on optical beam direction. We have confirmed that the extrinsic absorption bands correspond to optical transitions in Ce3+ activator ions localized in two crystallographically non-equivalent CeI and CeII positions. We have estimated that oscillator force for the optical transitions in Ce3+ ions. The photoluminescence spectra excited by 3.49 eV photon energy UV laser contain three bands: ~2.96 eV, ~3.13 eV (CeI) and ~2.70 eV (CeII). The energy structure of electron traps in LSO has been studied with thermally stimulated luminescence, the crystals being exposed to UV with different spectral and energy parameters. All the experimental thermally stimulated luminescence curves contain at least two peaks at 345 and 400 K with a 4 : 1 intensity ratio attributable to electron traps at 0.92—0.96 and1.12—1.18 eV. LSO exposure to high pressure mercury lamp radiation having the highest energy has for the first time showed the presence of traps at 0.88 eV. A model of the energy structure of LSO has been developed. The luminescence mechanism in the material is more complex than purely intracenter one. We show that high excitation energies may lead to ionization by the mechanism hv a + Ce3+ = Ce4+ + e-. We have assumed that the storage of excitation energy involves not only Ce3+ activator but also the conduction band as well as trap states localized near the conduction band.
V. V. Siksin
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-3-229-240

Abstract:
The article describes the proposed new multifunctional ionization chamber (MIC) designed to measure dose profiles when the medical accelerator "Prometheus" is operating in the scanning "pencil beam" mode. A digital image acquisition detector (DIDE) with a tissue-equivalent water phantom is used to calibrate the accelerator before a radiation therapy session. The application of the CPPI on the beam of a proton accelerator operating in the mode of beam splitting into spots with a scanning beam is considered. The CDPI detector allows for a few accelerator pulses in on-line mode to see how the energy release of each spot is distributed over the area of the irradiated target, which is the actual calibration of the accelerator before the proton therapy session. During the proton therapy session, it is planned to install the MIC directly in front of the patient. The MIC chamber contains two ionization chambers operating simultaneously — a pad chamber (PC) operating on gas or "warm liquid" and a strip ionization chamber operating only on gas (SC). At the accelerator "Prometheus" it is proposed to use a MIC, which will be used in the mode of operation by the method of active scanning with a "pencil" proton beam. The use of the MIC operation is intended to control the density of the beam intensity during the irradiation of the "target" in the patient during the proton therapy session. In case of violation of the planned operating mode of the accelerator and the beam goes beyond the parameters preset before the session, the deviation detection control system (SDMS) will turn off the accelerator. The device of the readout electronics (SE) of the MIC and SKOO cameras is described. This proposed detector, including the MIC and SKOO camera and the reading electronics serving it, will improve the quality of the therapeutic beam supply, due to the accurate determination of the absorbed dose density supplied by the scanning beam to each spot of the irradiated target, and therefore the generated high dose distribution field will correspond to the irradiated volume of the patient and will increase the safety and control of patient exposure to the target. The PC included in the MIC is designed on a "warm liquid" (or gas) and is a high-precision ionization chamber with coordinate sensitivity over the width of the irradiated target. The SC included in the MIC operates on gas and controls the direction of the incident beam to a given spot in the target. A version of the charge-sensitive preamplifier (QCD) and the SE system designed for experimental verification of the MIC prototype has been developed. The SCOO circuit working in conjunction with the MIC camera allows you to control the predetermined parameters of the irradiation of the patient's target boundaries and turns off the accelerator if these parameters deviate from the initially specified ones.
, D. P. Radchenko, , P. A. Zaporotskov, A. V. Popkova
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-3-196-202

Abstract:
An urgent problem of radio engineering and radioelectronics nowadays is the synthesis of composite materials with preset parameters that can be used as electronics engineering materials. Of special interest are MW range wide-band electromagnetic radiation absorbers. Special attention is paid to materials on the basis of ferromagnetic metals that are capable of effectively absorbing and reflecting incident waves and having a clear nanostructure. Development of nanocapsulated metals will allow controlling the parameters of newly designed materials. This is achieved with the use of polymer matrices, e.g. pyrolyzed polyacrylonitrile (PPAN). This work is a theoretical study of a PPAN monolayer model containing pairs of transition metal atoms iron, nickel and cobalt which possess ferromagnetic properties, in Fe–Co, Ni–Co and Fe–Ni combinations, with silicon amorphizing admixture. We studied the geometrical structure of the metal composite systems which are modeled as PPAN molecular clusters the centers of which are voided of six matrix material atoms, the resultant defects (the so-called pores) being filled with pairs of the metal atoms being studied. The metal containing monolayer proved to be distorted in comparison with the initially planar PPAN monolayer. We plotted single-electron spectra of the composite nanosystems and characterized their band gaps. The presence of metal atoms reduces the band gap of a metal composite as compared with pure PPAN. We determined the charges of the metals and found electron density transfer from metal atoms to their adjacent PPAN monolayer atoms. We calculated the average bond energy of the test metal composite systems and proved them to be stable. The studies involved the use of the density functional theory (DFT) method with the B3LYP functional and the 6-31G(d) basis.
V. N. Mordkovich, , , A. V. Leonov
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-2-109-115

Abstract:
The article is devoted to the issues of numerical simulation of field Hall sensors based on the "silicon on insulator" structure with two control gates. To solve the problem, a two-level local-one-dimensional computational model is used. At the first level, a series of one-dimensional Schrödinger—Poisson equations are solved, which describe the distribution of the electron density across the heterostructure in different sections. The obtained information is transmitted to the second level, where the current characteristics of the element are calculated. The numerical simulation results are compared with the experimental data obtained for field Hall sensors. Comparative analysis shows good agreement between calculated and experimental data. The developed computer model makes it possible to carry out a multivariate analysis of various heterostructures, which creates the basis for optimizing devices of the class under consideration.
S. A. Adarchin, V. G. Kosushki, V. M. Gurin, , M. S. Vasyutin, V. G. Bybenin
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-2-134-141

Abstract:
The problems of increasing the reliability of microelectromechanical systems are considered on the example of an automobile voltage regulator. A model of the process is proposed and a study of the effect of temperature on the formation of stress fields in semiconductor structures of active elements of the controller is carried out. The studies assumed of a possible reason for the change in the parameters of the regulator due to the appearance of defects in the crystal structure of the semiconductor material in the structures of integrated voltage regulators. For the study, a mathematical model was proposed that describes the behavior of a semiconductor element of a real car voltage regulator. It was found that the distribution of stresses in the structures is uneven and the maximum value of stresses reaches the edges., An increase in temperature gradients in the structures of regulators leads to the formation of dislocations that change the electrical characteristics of devices. As a result of modeling, it has been established that thermoelastic stresses arising in the process of manufacturing and functioning of semiconductor structures of a regulator in regulators of this type can cause a change in the structure of a semiconductor device due to relaxation of elastic stresses at dislocations. in cars. Measures are proposed, including thermostating of the sensitive elements of microelectromechanical structures, which will increase their service life.
V. A. Tkachenko, D. G. Baksheev, O. P. Sushkov
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-2-142-150

Abstract:
Предложена простая модель для описания самоорганизации локализованных зарядов и квантового рассеяния в нелегированных структурах GaAs/AlGaAs, в которых двумерный газ электронов, либо дырок создается соответствующим напряжением на затворе. Предполагается, что в такой структуре металл—диэлектрик—нелегированный полупроводник доминирует рассеяние носителей на локализованных поверхностных зарядах, которые могут находиться в любой точке плоскости, имитирующей интерфейс между GaAs и диэлектриком. Предложенная модель рассматривает эти поверхностные заряды и соответствующие заряды изображения в металлическом затворе как замкнутую систему в термостате. Электростатическая самоорганизация для данной системы в состояниях термодинамического равновесия исследована численно с помощью алгоритма Метрополиса в широком диапазоне температур. Показано, что при T > 100 К простая формула, выведенная из теории двумерной однокомпонентной плазмы дает почти такое же поведение структурного фактора при малых волновых числах, как алгоритм Метрополиса. Времена рассеяния затворно-индуцированных носителей описываются формулами, в которых структурный фактор характеризует замороженный беспорядок в данной системе. В этих формулах определяющим является поведение структурного фактора при малых волновых числах. Расчет по этим формулам при беспорядке, отвечающем бесконечной T, дал в два-три раза меньшие времена рассеяния, чем в соответствующих экспериментах. Мы нашли, что теория согласуется с экспериментом при температуре замерзания беспорядка T ≈ 1000 К в случае образца с двумерным электронным газом и T ≈ 700 К для образца с двумерным дырочным газом. Найденные величины являются оценкой сверху температуры замерзания в изучаемых структурах, поскольку модель игнорирует другие источники беспорядка кроме температуры.
A. A. Sleptsova, S. V. Chernykh, Д. А. Подгорный, I. A. Zhilnikov
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-2-127-133

Abstract:
Рассмотрено влияние режимов нанесения пассивирующих диэлектрических пленок нитрида кремния SiNx методом плазмохимического осаждения из газовой фазы в индуктивно-связанной плазме (ICP CVD) на параметры транзисторов с высокой подвижностью электронов (HEMT) на основе гетероструктур AlGaN/GaN. На основании результатов исследования параметров полученных слоев диэлектрического материала определено влияние RF и ICP мощностей, соотношения потоков рабочих газов на скорость роста пленок и их совершенство, а также их влияние на вольт-амперные характеристики пассивируемых HEMT. Скорость осаждения при увеличении RF мощности практически не менялась, однако при увеличении ICP мощности наблюдался ее рост. При этом крутизна транзистора сильно снижалась с ростом RF мощности, ее максимум достигался при минимальной мощности RF = 1 Вт. В начальный момент роста, даже при невысоких значениях RF мощности (уже при 3 Вт), структура транзистора становилась полностью неработоспособной. Показано, что процесс осаждения диэлектрика для пассивации HEMT необходимо начинать при максимально низких значениях RF мощности. Отработан технологический процесс пассивации AlGaN/GaN СВЧ HEMT, позволяющий осаждать конформные пленки и получать низкие токи сток—исток транзисторов в закрытом состоянии без ухудшения характеристик в открытом состоянии — на уровне не более 15 и 100 мкА соответственно для общей ширины Т-образного затвора 1,25 и 5 мм (Uз = –8 В и Uс-и = 50 В).
I. N. Ganiev, F. A. Aliev, X. O. Odinazoda, A. M. Safarov, P. Usmonov
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-2-151-161

Abstract:
Экономическая целесообразность применения алюминия в качестве проводникового материала объясняется благоприятным соотношением его стоимости и стоимости меди. Немаловажным является и то, что стоимость алюминия в течение многих лет практически не меняется.При использовании проводниковых алюминиевых сплавов для изготовления тонкой проволоки, обмоточного провода и т. д. могут возникнуть определенные сложности в связи с их недостаточной прочностью и малым числом перегибов до разрушения. В последние годы разработаны алюминиевые сплавы, которые даже в мягком состоянии обладают прочностными характеристиками, позволяющими использовать их в качестве проводникового материала.Одним из перспективных направлений использования алюминия является электротехническая промышленность. Проводниковые алюминиевые сплавы типа E-AlMgSi (алдрей) являются представителями данной группы сплавов. В работе представлены результаты исследования температурной зависимости теплоемкости, коэффициента теплоотдачи и термодинамических функций алюминиевого сплава E-AlMgSi (алдрей) с висмутом. Исследования проведены в режиме «охлаждения».Показано, что с ростом температуры теплоемкость и термодинамические функции сплава E-AlMgSi (алдрей) с висмутом увеличиваются, а значение энергия Гиббса уменьшается. Добавки висмута до 1 % (мас.) уменьшают теплоемкость, коэффициент теплоотдачи, энтальпию и энтропию исходного сплава и увеличивают энергию Гиббса.
V. M. Timokhin, V. M. Garmash, V. A. Tedzhetov
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-2-99-108

Abstract:
To implement the technology of thermally stimulated diagnostics of anisotropy and optical axes of crystals, the sample is thermostated at a temperature not exceeding the melting point, an electric field not exceeding the breakdown field is applied to the sample, polarization is produced for a time greater than the relaxation time at this temperature. After that, without disconnecting the electric field, cooling to the temperature of liquid nitrogen is performed, then the field is switched off, the sample is linearly heated to a temperature above the polarization temperature and the obtained thermally stimulated depolarization (TSD) spectra taken along and perpendicular to the optical axis of the sixth order C6 crystal are examined. When comparing the obtained spectra, the presence of anisotropy is determined, and the exact direction of the optical axes is determined by the magnitude and presence of the TSD maxima.
P. V. Shalaev, P. A. Monakhova, S. A. Tereshchenko
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-2-116-126

Abstract:
Five samples of colloidal dispersions of gold nanorods with various aspect ratio were studied using methods based on light scattering. Transmission electron microscopy was used as a reference method. The advantages and disadvantages of the dynamic light scattering and nanoparticle tracking analysis methods for determination of the geometric parameters of nanoparticles, their concentration, monodispersity, as well as for detection of large aggregates and quasispherical impurities were given. It was shown that the method of depolarized dynamic light scattering can be used for determination of the geometric parameters of liquid dispersions of colloidal gold nanorods. Moreover, it was found that the presence of large impurities or particle aggregates in the sample strongly affects the measurement results. The presence of large particles in the dispersion can be determined using dynamic light scattering or nanoparticle tracking analysis methods. The method of dynamic light scattering was also found to be more sensitive to the presence of even a small amount of large impurities or aggregates in the sample. The monodispersity of a liquid dispersion of nanorods can also be estimated by dynamic light scattering and nanoparticle tracking analysis methods, and, comparing to electron microscopy, the measurement results can be considered more statistically reliable due to the analysis of a larger number of particles. It was found that the increase of spherical particles concentration in the composite dispersion of nanospheres and nanorods leads to a decrease in the contribution of the rotational mode in the total scattering intensity. In addition, the concentration of quasispherical impurities in samples of liquid dispersions of colloidal gold nanorods was calculated based on measurements of the depolarization degree of scattered light.
I. N. Ganiev, A. P. Abdulakov, J. H. Jayloev, U. Sh. Yakubov, A. G. Safarov, V. D. Abulkhaev
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-1-86-93

Abstract:
The economic feasibility of using aluminum as a conductive material is explained by the favorable ratio of its cost to the cost of copper. It is also important that the cost of aluminum for many years remains virtually unchanged. When using conductive aluminum alloys for the manufacture of thin wire, winding wire, etc. Certain difficulties may arise in connection with their insufficient strength and a small number of kinks before fracture. In recent years, aluminum alloys have been developed, which even in a soft state have strength characteristics that allow them to be used as a conductive material. One of the promising areas for the use of aluminum is the electrical industry. Conducting aluminum alloys of the E-AlMgSi type (Aldrey) are representatives of this group of alloys. The paper presents the results of a study of the temperature dependence of heat capacity, heat transfer coefficient, and thermodynamic functions of an aluminum alloy E-AlMgSi (Aldrey) with bismuth. Research conducted in the "cooling" mode. It was shown that the temperature capacity and the thermodynamic functions of the alloy E-AlMgSi (Aldrey) with bismuth increase with temperature, and the Gibbs energy decreases. Additives of bismuth up to 1 wt.% Reduce heat capacity, heat transfer coefficient, enthalpy and entropy of the initial alloy and increase the value of Gibbs energy.
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-1-5-56

Abstract:
Lithium niobate (LiNbO3) and lithium tantalate (LiTaO3) are among the most important and most widely used materials of coherent and nonlinear optics, as well as acoustics. High degree of uniformity and reproducibility has become the foundation of technology for manufacturing high-quality crystals, absorbed by many suppliers around the world. However, the above areas do not limit the use of LiNbO3 and LiTaO3 due to their unique piezoelectric and ferroelectric properties. One promising application of crystals is the design of electromechanical transducers for precision sensors and actuators. In this respect, the high thermal stability of the piezoelectric and mechanical properties, the lack of hysteresis and creep make it possible to create electromechanical converters with wide operating temperature range, that is beyond the capability of commonly used ferroelectric ceramics. The main advantage of LiNbO3 and LiTaO3 over other single-crystal piezoelectrics is ferroelectric domain structure regulation toward targeted impact on the device characteristics. One of the most striking examples of electromechanical transducer design through domain engineering is the formation of a so-called bidomain ferroelectric structure in crystal. It represents a single-crystalline plate with two macrodomains with opposite directions of spontaneous polarization vectors separated by a charged domain wall. High switching fields make inversion domains stable at temperatures up to 1000 °C. This review summarizes the main achievements in the formation of bidomain structure and near surface inversion domains in LiNbO3 and LiTaO3 crystals. We present the domain structure virtualization methods in crystals and non-destructive methods for controlling the domain boundary position. The report contains a comparative analysis of the methods for forming inversion domains in crystals, and the patterns and technological control methods of the domain structure are discussed. The basic physical models have been proposed in the literature to explain the effect of the inversion domains formation. In the present paper we outline what one sees as strengths and weaknesses of these models. The strategies of crystallographic cut selection to create devices based on bidomain crystals are briefly discussed. We provide examples of the implementation of devices based on bidomain crystals such as actuators, sensors, acoustic transducers, and waste energy collection systems.
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-1-71-77

Abstract:
The influence of thermocycling annealing processes on the oxygen ordering degree (order parameter) in theYBa2Cu3O7-δ single crystals have been studied. It was determined that an increase in the critical temperature of the onset of the transition to the superconducting state during step annealing procedures is consistent with decrease of the σс/σаb parameter. This fact indicates the redistribution of the electronic density between the Cu(2)O2 and Cu(1)O1-d structurally-inhomogeneous planes, due to the formation of the oxygen long-range ordering in the O(4)—Cu(1)—O(4) linear groups along the (b) crystal structure axis of the unit cell, and removal of the oxygen defects in the square nets of the Cu(2)O2 planes. The existence of a critical value of the conductivity anisotropy σс/σаb, below which its behavior does not correlate with the change of Т с, has been proved. In this case, the increase of Тс and the orthorhombic distortion of the crystal structure at the isothermal annealing processes occur due to the amplification of the «interlayer» interaction between the Cu(2)О2 and Cu(1)О1-δ planes. As a result, the contribution of the Cu(1)О1-δ chain layers in the electronstate density on the Fermi level increases. These layers could be the superconducting ones by means of the Cooper pairs tunneling from the Cu(2)О2 planes, forming the induced superconductivity there.
, Л. Фельсберг,
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-1-57-70

Abstract:
Materials properties affecting EC device operation are discussed based on an analytically tractable model of a layered EC refrigerator. Special attention was paid to thermal and interface thermal resistances. Estimates of the average cooling power of a stacked MEMS-based EC refrigerator were made.
U. A. Mar’Ina, V. A. Vorob’Ev, A. P. Mar’In
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 23; https://doi.org/10.17073/1609-3577-2020-1-78-85

Abstract:
Представлен обзор известных люминесцентных материалов на основе галлата кальция CaGa2O4, излучающих в видимой и инфракрасной (ИК) области спектра. На сегодняшний день ИК-люминофоры исследованы мало, но их практическое применение представляет интерес. Твердофазным методом получены образцы CaGa2O4, активированные редкоземельными ионами Yb3+. Исследованы структурные и люминесцентные свойства состава CaGa2O4 : Yb3+. При возбуждении CaGa2O4 : Yb3+ излучением с длиной волны 940 и 980 нм зарегистрирована люминесценция в диапазоне 980—1100 нм. На основании данных о строении электронных уровней в ионах Yb3+ сделан вывод о том, что возбуждение и излучение происходят непосредственно в ионах Yb3+ при пассивном участии решетки основания. В спектрах люминесценции имеется три максимума на длинах волн 993, 1025 и 1080 нм. Излучение в этих полосах обусловлено оптическими переходами электронов из возбужденного в основное состояние в ионах Yb3+. Изучена зависимость интенсивности люминесценции в полосе 993 нм от концентрации ионов активатора Yb3+. Установлено, что введение в состав люминофора ионов Na+ повышает интенсивность ИК-люминесценции. Предложен оптимальный состав люминофора (Ca1-x-yYbxNay)Ga2O4, при котором интенсивность люминесценции в полосе 993 нм максимальна.
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-4-298-301

Abstract:
In the modern world, knowledge and high technologies determine the effectiveness of the economy, can radically improve the quality of life of people, modernize infrastructure and public administration, and ensure law and order and security. The creation of a research infrastructure based on a high-performance hybrid cluster enabled detailed calculations of complex phenomena and processes without full-scale experiments. It has become possible to most efficiently apply modern methods of multiscale computer modeling when developing prototypes of new materials with desired properties for their further synthesis. Such approaches can significantly reduce the cost and speed up the development of modern technologies for producing new semiconductor materials for nanoelectronics, composite materials for the aerospace industry and others. Thus, the use of multiscale modeling methods in combination with the use of high-performance software tools made it possible to create a computer model of a nanoscale heterostructure, develop tools for predictive computer modeling of the physical structure of nanoelectronic devices, the neuromorphic architecture of multilevel memory devices, defect formation in composite materials, and others.
E. N. Muratova, , K. V. Chernyakova,
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-4-241-245

Abstract:
In this work, we studied the thermal characteristics of flat heaters made of aluminum with a strip heating element in the form of carbon fiber. In order to provide the necessary insulation of the heating element from the metal base, a layer of porous anodic aluminum oxide with a thickness of 20 μm was formed on the aluminum surface. The ends of the carbon fiber filament were metallized with a layer of copper for subsequent soldering during the assembly of the electric heater. The carbon fiber filament of electric heater had an electrical resistance of 60 Ohms. Studies of the propagation of heat fluxes in the volume of a board made of aluminum with nanoporous aluminum oxide were carried out using thermal imaging measurements. The paper presents the dependence of temperature changes on the surface of the lid of a heating element made of aluminum and on the opposite side — heat transfer side with heating time. The results showed that the heat generated by a linear heating element of carbon fiber, quickly distributed throughout the entire volume of the aluminum plate of the heating element. This indicates a high thermal conductivity of the aluminum base of the heater, the parameters of which allow to achieve the required thermal characteristics of the heater.
O. A. Tkachenko, D. G. Baksheev
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-4-290-297

Abstract:
Magnetotransport in submicron devices formed on the basis of GaAs/AlGaAs structures is simulated by the method of nonequilibrium Green functions. In the one-particle approximation, the influence of a perpendicular magnetic field on electron transmission through a quasi-one-dimensional quantum dot and the Aharonov—Bohm interferometer is considered. Two-terminal conductance and magnetic moment of the devices are calculated. Two-dimensional patterns of equilibrium (persistent) currents are obtained. The correlations between energy dependences of magnetic moment and conductance are considered. For the quasi-one-dimensional quantum dot, regular conductance oscillations similar to the ABOs were found at low magnetic fields (0.05—0.4 T). In the case of a ring interferometer, the contribution to the total equilibrium current and magnetic moment at a given energy can change sharply both in magnitude and in sign when the magnetic field changes within the same Aharonov—Bohm oscillation. The conductance through the interferometer is determined not by the number of propagating modes, but rather by the influence of triangular quantum dots at the entrances to the ring, causing back scattering. Period of calculated ABOs corresponds to that measured for these devices.
I. V. Matyushkin
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-4-253-261

Abstract:
A general set of ideas related to the memristors modeling is presented. The memristor is considered to be a partially ordered physical and chemical system that is within the “edge of chaos“ from the point of view of nonlinear dynamics. The logical and historical relationship of memristor physics, nonlinear dynamics, and neuromorphic systems is illustrated in the form of a scheme. We distinguish the nonlinearity into external ones, when we describe the behavior of an electrical circuit containing a memristor, and internal ones, which are caused by processes in filament region. As a simulation model, the attention is drawn to the connectionist approach, known in the theory of neural networks, but applicable to describe the evolution of the filament as the dynamics of a network of traps connected electrically and quantum-mechanically. The state of each trap is discrete, and it is called an “oscillator“. The applied meaning of the theory of coupled maps lattice is indicated. The high-density current through the filament can lead to the need to take into account both discrete processes (generation of traps) and continuous processes (inclusion of some constructions of solid body theory into the model).However, a compact model is further developed in which the state of such a network is aggregated to three phase variables: the length of the filament, its total charge, and the local temperature. Despite the apparent physical meaning, all variables have a formal character, which is usually inherent in the parameters of compact models. The model consists of one algebraic equation, two differential equations, and one integral connection equation, and is derived from the simplest Strukov’s model. Therefore, it uses the “window function” approach. It is indicated that, according to the Poincare—Bendixon theorem, this is sufficient to explain the instability of four key parameters (switching voltages and resistances ON/OFF) at a cycling of memristor. The Fourier spectra of the time series of these parameters are analyzed on a low sample of experimental data. The data are associated with the TiN/HfOx/Pt structure (0 < x < 2). A preliminary conclusion that requires further verification is the predominance of low frequencies and the stochasticity of occurrence ones.
P. A. Sechenykh
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-4-268-271

Abstract:
Information about the structure and properties of materials is especially important when working with micro-and nanoscale objects due to the high complexity of their obtaining. This makes it relevant to use computer modeling to predict the required characteristics of materials. Electronic, magnetic, mechanical, and other properties of crystalline substances are determined by their structure-the periodicity of the lattice and the symmetry of the unit cell. This article discusses metal oxides with the general chemical formulas MeO (metals: Ca, Cd, Mg), MeO2 (metals: Hf, Ce, Zr), Me2O3 (metals: Er, Nd, Sc, Mn, Tl) and Me3O4 (using Fe as an example) and a cubic symmetry type crystal lattice — structural types NaCl (rock salt), Fluorite, Bixbyite, Spinel accordingly. The paper describes the model of ion-atomic radii, which is widely used in the modeling of crystalline metal oxides. The application of the annealing simulation algorithm for calculating the metric parameters of the compounds under consideration is shown. The software implementation of the algorithm presented in this paper allows us to determine the coordinates of the atoms that are included in the elementary cell of the crystal lattice, calculate the lattice constant and the density of the packing of atoms in the crystal cell using the specified chemical formula and the space group symmetry. These structural characteristics can be used as input parameters for determining electronic, magnetic, and other properties. The article compares the values of lattice constants obtained as a result of modeling with experimental data.
, , A. A. Sorokin, S. A. Denisov
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-4-302-307

Abstract:
The article discusses methods of consolidating scientific services of a digital platform for integrating a set of scientific services for various fields of science for conducting interdisciplinary research. Solutions for creating consolidated services can be widely used for multilevel, multiscale modeling in the field of materials science, which provides complex modeling at several levels of the hierarchy. Currently, this problem is being solved by creating multicomponent hierarchical software systems on corporate computing systems. With the advent of high-performance cloud computing platforms, it will be possible to order services for solving particular modeling problems as a scientific service. In this case, the tasks of complex hierarchical modeling will be solved by a consolidated service - a service providing sequential-parallel execution of complex modeling components in the form of specialized scientific services. The description of the processes for the provision of scientific services is based on the research methodology and is a research plan (the work process mapping), which describes a set of operations related to time and includes a list of necessary resources for their implementation. In modern conditions of the development of a microservice approach to the creation of computing systems and the evolution of the Service Oriented Architecture and of the Enterprise Service Bus integration, special attention is paid to the problems of efficient integration of platform services. The paper proposes to supplement the existing description of a scientific service with the possibility of ordering a third-party service based on agile integration. This approach will allow at the present stage of development of service architectures to overcome the shortcomings of centralized systems such as Enterprise Service Bus and take advantage of the elasticity of cloud computing and a microservice approach to creating information and computing systems.
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-4-246-252

Abstract:
Models that describe bipolar resistive switching in planar microstructures based on oxide compounds (Bi2Sr2CaCu2O8+x, Nd2-xCexCuO4-y) and bismuth selenide are considered. Metal-isolator-metal planar-type meristor heterostructures were investigated, in which the micro-size is formed by an electrode whose diameter is much smaller than the total size of the structure (it can be both Chervinsky-type microjunctions and film electric electrodes). Another important feature of these heterostructures is the presence of a surface layer several tens of nanometers thick with specific conductivity significantly reduced relative to volume. The change in the resistive properties of such heterostructures is caused by the formation or destruction of the conductive channel through the above-mentioned layer. Numerical simulation has shown that the bipolar resistive switching is significantly influenced by the electrical field distribution topology. A “critical field” model is proposed to describe experimentally observed memristor effects in investigated heterostructures. In this model it is assumed that the change in specific conductivity occurs in those parts of the surface layer where the electric field strength exceeds some critical value. The model of the “critical field” is based on the numerical calculation of the distribution of electrical potential on the distribution of specific conductivity in the structure. In addition, the model allowing to analyze the influence of electrodiffusion of oxygen ions on resistive switching in heterostructures based on Bi2Sr2CaCu2O8+x is considered. At numerical realization of the models a combination of the integro-differential approximation of the differential equations, the multi-grid approach for localization of heterogeneities of physical characteristics, the iterative decomposition method and composite adaptive meshes was used. It allowed tracking the processes under investigation with necessary accuracy. The comparison of simulation results with experimental data is presented.
N. N. Balan, V. V. Ivanov, A. V. Kuzovkov, E. V. Sokolova, E. S. Shamin
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-4-279-289

Abstract:
The article gives an overview of the main currently used models for the formation of photoresist masks and the problems in which they are applied. The main stages of «full physical» modeling of mask formation are briefly considered in the case of both traditional DNQ photoresists and CA photoresists. The concept of compact models (VT5 and CM1), which predict the contour of the resist mask for a full-sized device topology is considered. Examples of some calculations using both full physical modeling and compact models are given. Using a full physical modeling of the resist mask formation the lithographic stack was optimized for a promising technological process. The optimum thickness ratios for the binary BARC used in the water immersion lithographic process are found. The problem of determining the optimal number of calibration structures that maximally cover the space of aerial image parameters was solved. To solve this problem, cluster analysis was used. Clustering was carried out using the k-means method. The optimal sample size was from 300 to 350 structures, the mean square error in this case is 1.4 nm, which slightly exceeds the noise of the process for 100 nm structures. Using SEM images for calibrating the VT5 model allows reducing the standard error of 40 structures to 1.18 nm.
K. I. Volovich, S. A. Denisov
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-4-262-267

Abstract:
The article discusses the use of hybrid HPC clusters for the execution of software designed to calculate the electronic structure and atomic scale materials modeling. Modern software systems, which are designed to solve the problems of materials science, use the capabilities of various hardware computing accelerators to increase productivity. The use of such computing technologies requires the adaptation of application program code to hybrid computing architectures, which include classic central processing units (CPUs) and specialized graphics accelerators (GPUs).The use of large computing hybrid systems requires the development of methods for ensuring the workloading of such computing systems that will allow efficient use of computing resources and avoid equipment downtime.First of all, these methods should allow parallel execution of user applications using computational accelerators. However, in practice, software environments designed to solve application problems cannot be deployed in the same computing environment due to software incompatibility. In order to overcome this limitation and ensure the parallel execution of diverse types of materials science tasks, the creation of individual task execution environments based on virtualization technologies and cloud technologies.The continuation of virtualization technologies and the provision of cloud services is the construction of digital platforms. The article proposes the use of a digital platform for hosting scientific materials science services that provide calculations using various application software systems. Digital platforms make it possible to provide a unified user interface to scientific materials science services. The platform provides opportunities for finding the necessary scientific services, transferring source data and results between users, the platform and hybrid high-performance clusters.
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-4-272-278

Abstract:
The property of natural parallelization of matrix-vector operations inherent in memristor crossbars creates opportunities for their effective use in neural network computing. Analog calculations are orders of magnitude faster in comparison to calculations on the central processor and on graphics accelerators. Besides, mathematical operations energy costs are significantly lower. The essential feature of analog computing is its low accuracy. In this regard, studying the dependence of neural network quality on the accuracy of setting its weights is relevant. The paper considers two convolutional neural networks trained on the MNIST (handwritten digits) and CIFAR_10 (airplanes, boats, cars, etc.) data sets. The first convolutional neural network consists of two convolutional layers, one subsample layer and two fully connected layers. The second one consists of four convolutional layers, two subsample layers and two fully connected layers. Calculations in convolutional and fully connected layers are performed through matrix-vector operations that are implemented on memristor crossbars. Sub-sampling layers imply the operation of finding the maximum value from several values. This operation can be implemented at the analog level. The process of training a neural network runs separately from data analysis. As a rule, gradient optimization methods are used at the training stage. It is advisable to perform calculations using these methods on CPU. When setting the weights, 3—4 precision bits are required to obtain an acceptable recognition quality in the case the network is trained on MNIST. 6-10 precision bits are required if the network is trained on CIFAR_10.
, , Z. A. Goreeva, V. M. Kasimova
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-3-168-178

Abstract:
Рассмотрены особенности разработки и применения методик выполнения измерений коэффициентов преломления, основанных на многоугловых спектрофотометрических методах отражения. Описано влияние формы, размеров и обработки поверхности образцов на их спектральные зависимости отражения. Показана возможность определения коэффициентов преломления двумя спектрофотометрическими методами: по спектру отражения от одной грани при малом угле падения света, близком к нормальному, и методом отражения при падении света при угле Брюстера. Метод отражения при угле падения, близком к нормальному, может применяться в случае непоглощающего образца, который характеризуется коэффициентом экстинкции не превышающем (10-6—10-4). Этот метод является «экспресс-методом», поскольку позволяет сразу получать дисперсионную зависимость коэффициента преломления. Метод позволяет измерять дисперсионные зависимости коэффициентов преломления для образцов, форма которых исключает многократные отражения: пластин с одной шлифованной стороной; пластин большой толщины, полированных с двух сторон; призм или пластин с неплоскопараллельными гранями. При измерении по методу Брюстера не предъявляются требования к значению коэффициента экстинкции образца (поглощению), можно использовать образцы любой формы, в том числе, полированные с двух сторон пластины малой толщины. Однако получаемые значения коэффициентов преломления дискретны, требуется накопление большого массива результатов измерений. Определена точность измерений обоих методов, которая составляет Δ = ±0,001 при доверительной вероятности P = 0,95. Применимость спектрофотометрических методик измерения показана для образцов гадолиний-алюминий-галлиевого граната, относящегося к кристаллам кубической сингонии и характеризующегося наличием одного коэффициента преломления. Показано, что значения коэффициентов преломления, полученные данными методами, хорошо соотносятся в пределах точности измерений.
T. V. Kritskaya, V. N. Zhuravlev, V. S. Berdnikov
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-3-158-167

Abstract:
The process of growing silicon single crystals by the Czochralski method has been improved, which involves the use of two argon streams. 1st, the main flow, 15—20 nl/min, is directed from top to bottom along the growing single crystal. It captures the reaction products of the melt with a quartz crucible (mainly SiO), removes them from the chamber through a nozzle in the lower part of the chamber and provide dislocation-free single crystals from large loads. Similar processes are known and widely used in world practice since the 1970s. 2nd, additional flow, 1.5—2 nl/min, is directed at an angle of 45° to the surface of the melt in the form of jets from nozzles arranged in a ring. This flow initiates the formation of a region of turbulent melt flow, which isolates the crystallization front from convective flows enriched with oxygen, and also enhances the evaporation of carbon from the melt. It is confirmed that the oxygen evaporated from the melt (in the form of SiO) is a «transport» for non-volatile carbon. Carrying out industrial processes showed that the carbon content in the grown single crystals can be significantly reduced, up to values smaller than in the feedstock. In single crystals grown using two argon streams, an increased macro- and micro-uniformity of the oxygen distribution, a significantly larger crystal length with a given, constant oxygen concentration, were also recorded. Achieving a carbon concentration of 5 to 10 times less than in the feedstock is possible with small amounts of argon for melting (15—20 nl/min compared to 50—80 nl/min used in conventional processes. The use of an additional argon flow, which has an outflow intensity 10 times lower than that of the main flow, does not distort the nature of the flow around the single crystal surface (“axial”), does not disrupt the growth of a dislocation-free single crystal, does not increase the density of microdefects, which indicates the absence of changes in temperature gradients and thermal shock leading to thermal stresses in a single crystal.
, I. S. Kolbin
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-3-190-196

Abstract:
In this work, we calculate the effective thermal conductivity coefficient for a binary semiconductor heterostructure using the GaAs/AlAs superlattice as an example. Different periods of layers and different ambient temperatures are considered. At the scale under consideration, the use of models based on the Fourier law is very limited, since they do not take into account the quantum-mechanical properties of materials, which gives a strong discrepancy with experimental data. On the other hand, the use of molecular dynamics methods allows us to obtain accurate solutions, but they are significantly more demanding on computing resources and also require solving a non-trivial problem of potential selection. When considering nanostructures, good results were shown by methods based on the solution of the Boltzmann transport equation for phonons; they allow one to obtain a fairly accurate solution, while having less computational complexity than molecular dynamics methods. To calculate the thermal conductivity coefficient, a modal suppression model is used that approximates the solution of the Boltzmann transport equation for phonons. The dispersion parameters and phonon scattering parameters are obtained from first-principle calculations. The work takes into account 2-phonon (associated with isotopic disorder and barriers) and 3-phonon scattering processes. To increase the accuracy of calculations, the non-digital profile of the distribution of materials among the layers of the superlattice is taken into account. The obtained results are compared with experimental data showing good agreement.
K. I. Volovich, S. A. Denisov,
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-3-197-201

Abstract:
The article is devoted to the problem of solving scientific problems in the field of high-performance computing systems. An approach to solving a certain kind of problems in materials science is the use of mathematical modeling technologies implemented by specialized modeling systems. The greatest efficiency of the modeling system is shown when deployed in hybrid high-performance computing systems (HHPC), which have high performance and allow solving problems in an acceptable time with sufficient accuracy. However, there are a number of limitations that affect the work of the research team with modeling systems in the HHPC computing environment: the need to access graphics accelerators at the stage of development and debugging of algorithms in the modeling system, the need to use several modeling systems in order to obtain the most optimal solution, the need to dynamically change settings modeling systems for solving problems. The solution to the problem of the above limitations is assigned to an individual modeling environment functioning in the HHPC computing environment. The optimal solution for creating an individual modeling environment is the technology of virtual containerization. An algorithm for the formation of an individual modeling environment in a hybrid high-performance computing complex based on the «docker» virtual containerization system is proposed. An individual modeling environment is created by installing the necessary software in the base container, setting environment variables, installing custom software and licenses. A feature of the algorithm is the ability to form a library image from a base container with a customized individual modeling environment. In conclusion, the direction for further research work is indicated. The algorithm presented in the article is independent of the implementation of the job management system and can be used for any high-performance computing system.
K. L. Enisherlova, E. M. Temper, Yu. V. Kolkovsky, B. K. Medvedev, S. A. Kapilin
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-3-202-211

Abstract:
В полевых транзисторах на основе широкозонных нитридных гетероструктур широко используются диэлектрические слои в качестве как одного из основных элементов в активных областях приборов, так и пассивирующих слоев. К диэлектрикам предъявляются жесткие требования по высокой диэлектрической проницаемости, большой ширине запрещенной зоны, сплошности покрытия. Кроме того, пленки должны выдерживать высокие электрические поля и иметь низкую плотность поверхностных состояний на границе диэлектрик/полупроводник. Для этих целей в качестве эффективных покрытий обычно используются низкотемпературные пленки, выращенные с помощью плазмохимического осаждения из газовой фазы, атомно-слоевого осаждения (ALD) и плазменно-стимулированного осаждения. Для гетероструктур AlGaN/GaN наиболее перспективными и чаще всего используемые являются пленки ALD Al2О3, SiNх (Si3N4), SiON, ALD AlN.Исследовано влияние пассивирующих покрытий ALD Al2O3, SiNx и SiON разной толщины на изменение заряда и плотности состояний гетероструктур AlGaN/GaN. Электрофизические параметры структур оценивались с помощью C—V-характеристик, измеренных на разных частотах, и I—V-характеристик. На основании рассмотренных зонных диаграмм структур при разном управляющем напряжении и оценки элементного состава пленок методом Оже-спектроскопии показано, что причиной образования большого положительного заряда при нанесении пленок ALD Al2O3 и SiNx является возникновение дополнительного пьезоэлектрического заряда в буферном слое AlGaN. Показано, что использование пленок SiON с концентрацией кислорода в них более 3 % не приводит к формированию дополнительного положительного заряда, но может вызывать флуктуации тока при измерении I—V-характеристик. Рассмотрен возможный механизм транспорта носителей в области пространственного заряда, приводящий к таким флуктуациям.
V. V. Sleptsov, , , D. Yu. Kukushkin, A. A. Nagaev
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-3-212-218

Abstract:
In this paper, promising nanocomposite materials based on carbon and titanium are considered. It is shown that the use of a highly porous matrix is of particular interest. Materials based on such matrices have minimal weight and high strength characteristics. The paper also describes composites based on porous carbon fibers with metal oxides. The directions for producing composites can be divided into three types: matrix method, coating of finished nanoparticles with an inert shell, and the formation of nanoparticles and matrices in one process. The coating of nanoparticles with an inert shell prevents their oxidation and preserves the necessary magnetic properties. When using methods such as IR pyrolysis, arc evaporation forms third-party metal-carbon phases that pollute the resulting material. To avoid this, reducing agents are used, for example, hydrogen when coking nanoparticles in a methane plasma current restores metal particles from its Sol-gel and prevents them from reacting with carbon. But with this method, it is difficult to control the particle size. Using a ready-made matrix allows you to control the size of nanoparticles. However, this method uses high temperatures, and sometimes hydrogen, which complicates the production process. The main problem in the field of nanocomposites is the search for more technological, simple, cheap and environmentally friendly methods for obtaining nanocomposites with high performance characteristics. The developed technology for forming the pore space of the initial carbon matrix does not have the above disadvantages. This technology has a simple, cheap, environmentally friendly design. high temperatures are not used in the process of producing nanocomposites and third-party metal-carbon phases are not formed. The resulting nanocomposite materials were used as electrodes for ultra-high-volume capacitor structures. When studying the capacitance and electrical characteristics of samples, it was found that the formation of metal on a porous carbon matrix can significantly reduce the internal resistance of the cell and increase the specific energy consumption.
, , M. V. Yarmolich, , , , A. V. Petrov, , A. L. Zhaludkevich, S. E. Demyanov
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-3-149-157

Abstract:
Исследована последовательность фазовых превращений в процессе кристаллизации Sr2CrMoO6-δ из стехиометрической смеси простых оксидов SrCO3 + 0,5Cr2O3 + MoO. Установлено, что фазообразование хромомолибдата стронция протекает через ряд последовательно-параллельных стадий. Согласно данным дифференциально-термического и термогравиметрического анализов, обнаружено, что в температурном диапазоне 300—1300 К наблюдается пять ярко выраженных эндотермических эффектов. При изучении последовательности фазовых превращений в процессе синтеза двойного перовскита обнаружено, что основными сопутствующими соединениями являются SrCrO3, SrMoO4 и Sr2CrO4. При этом замечено, что с ростом температуры отжига от 300 до 1270 К в исходной смеси первоначально и практически одновременно появляются сложные соединения SrCrO4, SrCrO3 (350—550 К), а затем и SrMoO4, Sr2CrO4 (600—750 К). Показано, что с последующим увеличением температуры в интервале температур 940—1100 К концентрация фаз SrMoO4, Sr2CrO4 и SrCrO3 резко падает с появлением и ростом двойного перовскита Sr2CrMoO6-δ. При этом в интервале температур до 1120—1190 К основные рентгеновские рефлексы фазы Sr2CrO4 уменьшаются незначительно, тогда как интенсивность рентгеновских рефлексов фаз SrCrO3 и SrMoO4 снижается существенно больше и их содержание в образце при температуре 1170 К составляет не более 7,9 %. Анализ амплитудных значений производной степени превращения фаз SrCrO3, SrMoO4 и Sr2CrO4, при которых скорости их кристаллизации максимальны, показал, что для Sr2CrO4 величина |(dα/dt)|mах соответствует наибольшей температуре T = 1045 К. Это указывает на наличие кинетических трудностей при образовании фазы Sr2CrO4, которая в дальнейшем не исчезает, а при ее появлении наблюдается замедление роста двойного перовскита. На основании результатов, полученных при изучении динамики фазовых превращений для формирования однофазного Sr2CrMoO6-δ со сверхструктурным упорядочением Cr/Mo и улучшенными магнитными характеристиками, были применены прекурсоры SrCrO3 и SrMoO4 с использованием комбинированных режимов нагрева.
V. V. Siksin
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-3-228-236

Abstract:
The use of “warm liquid” tetramethylsilane (TMS) in ionization chambers for measuring dose profiles in water phantoms to prepare the accelerator for a proton therapy session is relevant. One of the promising areas of radiation therapy is proton therapy. To increase the conformality of proton therapy, it is important to know exactly the dose distributions from the energy release of the proton beam in the water phantom before conducting a proton therapy session. A television-type detector (TTD), which measures the profiles of the Bragg peak by the depth of the beam in the water phantom, helps to increase the accuracy of the dose distribution knowledge. To accurately determine the profile of the Bragg peak by the beam width in the water phantom, an additional method is proposed that will allow TTD to quickly determine the profile by the width of the Bragg peak in on-line mode. This prefix to the TTD will improve the quality of summing up the therapeutic beam-thanks to accurate knowledge of the profile by width, and therefore the formed high-dose distribution field will correspond to the irradiated volume in the patient and will increase the conformality of irradiation. The additional prefix to the TTD is designed on an organosilicon “warm liquid” and represents a high-precision ionization chamber with coordinate sensitivity along the width of the water phantom. The fully developed technology for obtaining “warm liquid” TMS allows creating both microdosimeters for proton therapy and detectors for measuring “dose profiles” in water phantoms during accelerator calibration. The considered prefix to the TTD detector - the calibrator meter of the dose field (KIDP) - can also be used independently of the TTD and with great accuracy measure the dose profiles of the Bragg peak in the water phantom, both in depth and width. KIDP can also be used to measure the outputs of secondary “instantaneous” neutrons and gamma quanta emitted from the water phantom orthogonally to the direction of the proton beam.
I. N. Ganiev, F. A. Aliev, H. O. Odinazoda, A. M. Safarov, J. H. Jayloev
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-3-219-227

Abstract:
Aluminum — a metal whose scope of application is constantly expanding. At present, aluminum and its alloys in a number of areas successfully displace traditionally used metals and alloys. The widespread use of aluminum and its alloys is due to its properties, among which, first of all, low density, satisfactory corrosion resistance and electrical conductivity, ability to apply protective and decorative coatings should be mentioned. All this, combined with the large reserves of aluminum in the earth’s crust, makes the production and consumption of aluminum very promising. One of the promising areas for the use of aluminum is the electrical industry. Conductive aluminum alloys type E-AlMgSi (Aldrey) are representatives of this group of alloys.One of the promising areas for the use of aluminum is the electrical industry. Conducting aluminum alloys of the E-AlMgSi type (Aldrey) are representatives of this group of alloys. The paper presents the results of a study of the temperature dependence of heat capacity, heat transfer coefficient, and thermodynamic functions of an aluminum alloy E-AlMgSi (Aldrey) with gallium. Research conducted in the “cooling” mode. It is shown that the temperature capacity and thermodynamic functions of the E-AlMgSi alloy (Aldrey) with gallium increase, while the Gibbs energy decreases. Gallium additives up to 1 wt.% Reduce the heat capacity, enthalpy, and entropy of the initial alloy and increase the Gibbs energy.
A. I. Prostomolotov, N. A. Verezub
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-3-179-189

Abstract:
An original modification of the directed crystallization method is considered as a multi-cassette process, which has comparative simplicity and high productivity. The basis of this research was domestic patents and technological research carried out at the National University of Science and Technology MISIS. As a result, mathematical models of the multi-cassette method were developed that allow both a three-dimensional radiative — conductive analysis of thermal processes in the entire volume of the hot zone and a two-dimensional analysis of convective — conductive heat transfer in a separate cassette. The parametric calculations carried out on their basis were aimed to the identifying an influence of locations and sizes of the hot zone components to a thermal field in the cassette unit; the establishing an influence of vertical heat supply equability to the cassette unit and an influence of heating power decrease during the plate crystallization, as well as to the determining an influence of small cassette design distortions and violation of cooling uniformity in its bottom part on the occurrence of convection and asymmetrical thermal field. By means of the conductive-radiative heat transfer model for the entire hot zone there were carried out parametric calculations and it was analyzed an influence of hot zone components (their locations and temperatures) on the heat exchange conditions at the cassette unit boundaries. By means of the conductive-convective model for a cassette it was determined that the boundary thermal conditions asymmetry, as well as an unstable vertical temperature gradient, result in the convective vortices and a significant deviation of the crystallization front from a flat shape. The calculations with using the convective mass transfer model showed that an increase of the crystallization rate by an order significantly increases a tellurium flux into the crystal, thereby substantially changing a melt composition near crystallization front and, thus, being a potential cause of dendritic growth. The reliability of the calculation results was checked on a number of tests, in which the influence of heat and mass transfer on the crystallization front shape was analyzed at cassette cooling rates corresponding to the growth processes of bismuth telluride polycrystals.
, , M. R. Predtechenskiy, А. Е. Безродный, V. V. Kirienko, A. V. Dvurechenskii
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-2-104-111

Abstract:
Бумага (buckypaper) из одностенных углеродных нанотрубок (ОУНТ) является перспективным материалом для большого числа вариантов применения, в которых требуется высокая удельная электро- и теплопроводность, а также высокая удельная прочность. Изотропные образцы buckypaper (BP) из ОУНТ сформированы фильтрацией дисперсии из ОУНТ для удаления растворителя. Для увеличения проводимости ВР производилась ориентация ОУНТ вдоль выделенного направления, а также дополнительное легирование ОУНТ в парах йода. Ориентация ОУНТ осуществлялась с помощью экструзии через щель раствора из ОУНТ. Проведено сравнение температурных зависимостей электропроводности изотропных, ориентированных и легированных образцов ВР для выявления механизма проводимости и роли ориентации ОУНТ. Показано, что ориентирование пучков ОУНТ вдоль выделенного направления позволяет увеличить проводимость ВР с 103 См/cм до ~ 104 См/cм, а легирование ориентированных образцов в парах йода увеличивает электропроводность еще на порядок. Механизм...
, , V. E. Gumiennik, , A. O. Konakov, , , A. A. Kharchenko
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; https://doi.org/10.17073/1609-3577-2019-2-73-83

Abstract:
Использование графена в электронике требует как экспериментального исследования процесса формирования высококачественных низкоомных контактов, так и углубления понимания механизмов электронного переноса в окрестности контакта металл/графен. В работе исследован транспорт носителей заряда в твистированном CVD графене, который декорирован электрохимически осажденными частицами Co, образующими омический контакт с графеновым слоем. Сопоставляются температурные и магнетополевые зависимости слоевого сопротивления R(T,B) исходного и декорированного твистированного графена на подложке из оксида кремния. Показано сосуществование отрицательного (при индукции магнитного поля ниже 1 Тл) и положительного (индукция выше 1 Тл) вкладов в магниторезистивный эффект в обоих типах образцов. Зависимости R(T,B) анализируются на основе теории двумерных интерференционных квантовых поправок к проводимости Друде с учетом конкуренции вклада от прыжкового механизма проводимости. Показано, что в изученной области температур (2–300 К) и магнитных полей (до 8 Тл) при описании транспорта носителей заряда в исследованном графене необходимо учитывать не менее трех интерференционных вкладов в проводимость: от слабой локализации, междолинного рассеяния и нарушения хиральности псевдоспина, а также короблением графена вследствие тепловых флуктуаций.
Page of 7
Articles per Page
by
Show export options
Select all