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Journal Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering

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V. V. Siksin
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; doi:10.17073/1609-3577-2019-1-45-52

Abstract:
The features of the development of the electronic path of the TV channel of the television type detector (TTD) are considered. It is noted that the mode of binning (addition of pixels) is the most difficult in technical implementation. Calculations are made to improve the mathematical model for the computer detector television type. The parameters of the analytical formula valid for proton energies from 30 to 250 MeV, based on the combination of functions of the parabolic cylinder, consistent with numerical methods and new experimental data, are determined. A list of theoretical papers describing the modified Bragg curve is given.Offers the possibility of a new approach to the description of dose field Bragg peak consisting in the application of the so-called «full experience» when the experimentally measured characteristics of the dose distribution of a system of equations in which the measured values are presented as a function of the so-called «amplitude dose field». The «amplitude dose field» are determined from the solution of this system of equations. The «amplitude dose field» depend on the z coordinates in the water phantom where, the z-axis of the beam direction and after determining the amplitudes from the system of equations described-certain amplitudes are used to quickly predict the measured characteristics of the dose distribution. The combination of the adaptive electronic pathway working independently without the participation of the operator during the experiment on the calibration of the accelerator and in determining the experimentally measured characteristics of the dose distribution, allows on-line to prepare the therapeutic accelerator «Prometheus» for a session with the patient.
V. E. Asadchikov, I. G. Dyachkova, D. A. Zolotov, Yu. S. Krivonosov, V. T. Bublik, A. I. Shikhov
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; doi:10.17073/1609-3577-2019-1-18-26

Abstract:
The method of two-crystal X-ray diffractometry is used to control the quality and perfection of monocrystalline silicon obtained by implantation of hydrogen ions and subsequent thermal annealing, which is used in a number of semiconductor technologies. The principal feature of this approach is the ability to quickly obtain reliable experimental results, which was confirmed in this paper by the use of X-ray topography. The presented data provide information on the state of the disturbed layer of silicon crystals of n-type conductivity (ρ = 100 Om ⋅ cm) by orientation (111), 2 mm thick, implanted by protons with energy E = 200, 300, 100 + 200 + 300 keV, dose D = 2 ⋅ 1016cm-2 and subjected to subsequent thermal treatment in the temperature range T from 100 to 900 °С. We have established a non-monotonic dependence of the integral characteristics of the disturbed layer, namely the average effective thickness Leff and the average relative deformation ∆а/а, on annealing temperature, with the maximum level of distortion in the field of temperature ∼300 °С, using the method of integral characteristics. Obtained data allowed to assess the general condition of disturbed layer during thermal treatment.
V. M. Kasimova, Sciprofile linkN. S. Kozlova, O. A. Buzanov, Sciprofile linkA. P. Kozlova, Sciprofile linkE. V. Zabelina
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; doi:10.17073/1609-3577-2019-1-27-34

Abstract:
Scintillation materials that can convert absorbed high-energy particles into photons of visible radiation find many applications, in particular in modern methods of medical imaging. Gd3Al2Ga3O12 : Ce is promising single crystal for use as a detecting crystal element of the positron emission tomographs due to its unique properties: high density, high light output, radiation hardness, etc. However, its scintillation kinetics currently limit the use of this crystal. Changing of these kinetics by codoping becomes a priority task, which is considered in many papers. The literature data analysis showed that the optical characteristics of such codoped crystals were not well enough studied or were not investigated at all. In this regard, the spectral dependences of transmission, absorption and reflection are measured using optical spectroscopy for Gd3Al2Ga3O12:Ce, Gd3Al2Ga3O12 : Ce,Ca and Gd3Al2Ga3O12 : Ce,Zr. Dispersion dependences of refractive in dices are obtained by approximating the refractive indices measured using the Brewster method. The approximation was carried out using the Cauchy equation. The material constants of this equation are estimated.
A. M. Kislyuk, Т. С. Ильина, Sciprofile linkI. V. Kubasov, D. A. Kiselev, A. A. Temirov, A. A. Turutin, M. D. Malinkovich, A. A. Polisan, Yu. N. Parkhomenko
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; doi:10.17073/1609-3577-2019-1-5-17

Abstract:
Сегнетоэлектрические кристаллы ниобата лития (LiNbO3) c искусственно сформированной доменной структурой находят широкое применение в оптических системах генерации кратных гармоник лазерного излучения, акустооптике, прецизионных актюаторах, датчиках вибрации и магнитного поля, в том числе предназначенных для применения при повышенных температурах, в перспективе — в запоминающих устройствах ЭВМ. Исследовано влияние заряженной междоменной границы на формирование индуцированных доменных структур в конгруэнтных кристаллах ниобата лития (LiNbO3) неполярного x-среза. Методами диффузионного отжига на воздухе вблизи температуры Кюри и инфракрасного отжига в бескислородной среде в образцах были сформированы би- и полидоменные сегнетоэлектрические структуры, содержащие заряженные доменные границы типа «голова-к-голове» и «хвост-к-хвосту». В режиме Кельвин-моды атомно-силового микроскопа (АСМ) исследован поверхностный потенциал в окрестности заряженной междоменной границы....
V. M. Timokhin, V. M. Garmash, V. A. Tedzhetov
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; doi:10.17073/1609-3577-2019-1-35-44

Abstract:
In practical application of crystals in optoelectronics and laser technology it is necessary to know the direction of optical axes and types of oscillatory centers, which is a relevant and necessary condition. In this paper, the infrared spectra of transmission and absorption of hexagonal crystals of lithium iodate α-LiIO3, grown by open evaporation in H2O and D2O solutions, as well as natural lamellar crystals of phlogopite and muscovite monoclinic crystal are investigated. The band gap width of the investigated crystals is determined by transmission spectra. In the absorption spectra there were determined activation energy and wavelength of the oscillatory centers that are associated with the vibrations of protons, hydronium ions Н3О+, protium H+, OH groups and molecules HDO. The good correlation of the parameters of infrared spectra with the spectra of thermally stimulated depolarization currents and NMR spectra has shown. The possibility of diagnostics of types of oscillatory centers by means of infrared spectra is considered, which also allows to find out the direction of optical axes. The obtained results allow to use IR spectra to determine not only the types of vibrational centers, but also the presence of anisotropy of the crystal lattice of the studied crystals.
Yu. S. Haiduk, Sciprofile linkA. A. Khort, M. A. Mokhovikov, Sciprofile linkA. A. Savitsky
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 22; doi:10.17073/1609-3577-2019-1-53-66

Abstract:
Nanocrystalline tungsten oxide (WO3), indium oxide (In2O3), cobalt oxide (Co3O4) and mixed composites with different WO3—In2O3 and WO3—Co3O4 ratios were obtained by the sol-gel method after calcination of xerogels at 400—600 °C. The morphology, phase composition, and structural features of the materials obtained were studied by X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. The increase in the gas sensitivity of the joint composition compared to the initial oxides can be explained by a decrease in the crystallite size and an increase in the specific surface, as well as by the dependence of the surface state of the grains on the composition. The highest sensory response to nitrogen dioxide in both compositions lies in the range of 130—150 °C, and to carbon monoxide, above 230 °C. Low-power planar nitrogen dioxide sensors with a sensitivity of << 1 ppm and power consumption ≤ 85 mW were produced.
N. S. Kozlova, E. V. Zabelina, M. B. Bykova, A. P. Kozlova
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 21; doi:10.17073/1609-3577-2018-3-146-155

Abstract:
Аннотация. Исследован процесс протекания токов короткого замыкания в кристаллах с низкотемпературными фазовыми переходами: сегнетовой соли NaKC4H4O6 • 4H2O и триглицинсульфата (CH2 • NH2 • COOH)3 • H2SO4. Испытания проведены на образцах полярных срезов без предварительной поляризации с симметричными индиевыми токопроводящими покрытиями. На всех образцах при комнатной температуре выявлено наличие токов короткого замыкания, которые сохраняются достаточно долго, и явление спадания тока со временем. Получены температурные зависимости токов короткого замыкания в диапазоне температур 16—45 °С для сегнетовой соли и 16—110 °С для триглицинсульфата. Токи короткого замыкания наблюдаются в исследованных кристаллах как в сегнетофазе, так и в парафазе. Показано, что при нагреве в сегнетофазе суммарный ток короткого замыкания определяется конкурирующими процессами: пиротоками и токами электрохимического разложения. В парафазе токи короткого замыкания являются токами электрохимического саморазложения. Показано, что протекание токов короткого замыкания через образцы полярных срезов кристаллов сегнетовой соли и триглицинсульфата обусловлено наличием собственной ЭДС, возникшей в результате электрохимического саморазложения противоположных поверхностей полярных срезов образцов при контакте с токопроводящими покрытиями вследствие анизотропии этих сторон. Предложена модель электрохимического саморазложения в таких кристаллах.
K. K. Abgarian, Sciprofile linkI. S. Kolbin
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 21; doi:10.17073/1609-3577-2018-3-175-181

Abstract:
The article discusses the calculation of the temperature regime in nanoscale AlAs/GaAs binary heterostructures. When modeling heat transfer in nanocomposites, it is important to take into account that heat dissipation in multilayer structures with layer sizes of the order of the mean free path of energy carriers (phonons and electrons) occurs not at the lattice, but at the layer boundaries (interfaces). In this regard, the use of classical numerical models based on the Fourier law is limited, because it gives significant errors. To obtain more accurate results, we used a model in which the heat distribution was assumed to be constant inside the layer, while the temperature was stepwise changed at the interfaces of the layers. A hybrid approach was used for the calculation: a finite−difference method with an implicit scheme for time approximation and a mesh−free model based on a set of radial basis functions for spatial approximation. The calculation of the parameters of the bases was carried out through the solution of the systems of linear algebraic equations. In this case, only weights of neuroelements were selected, and the centers and «widths» were fixed. As an approximator, a set of frequently used basic functions was considered. To increase the speed of calculations, the algorithm was parallelized. Calculation times were measured to estimate the performance gains using the parallel implementation of the method.
Sciprofile linkK. L. Enisherlova, B. K. Medvedev, E. M. Temper, V. I. Korneev
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 21; doi:10.17073/1609-3577-2018-3-182-193

Abstract:
In this paper are considers the effect of the microrelief, dislocation structure and other defects of the epitaxial layers of the source and drain regions of the nitride HEMT transistors on the parameters of the formed ohmic contacts. The studies were carried out directly on high−power microwave transistors made of GaN/AlGaN/GaN/SiC heterostructures. Ohmic burning contacts were formed using the compositions Ti—Al—Mo—Au and Ti—Al—Ni—Au. To estimation the structural features of the contact areas, the surface microrelief at the interface of the burned contact/AlGaN and the defects formed on its surface was studied. It is shown that the resistance of the source and drain regions is largely determined by the surface microstructure at the boundary. Experimentally shown is the formation of a conducting layer in AlGaN under the ohmic contacts. The possibility of the formation of a new type of structural defects with a high aspect ratio in the contact and active areas of the devices during the formation of ohmic burned contacts is demonstrated. It is shown that the appearance of high densities of such defects leads to an increase of the device leakage currents.
A. V. Pashkevich, A. K. Fedotov, Yu. V. Kasyuk, L. A. Bliznyuk, J. A. Fedotova, N. A. Basov, A. S. Fedotov, I. A. Svito, E. N. Poddenezhny
Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, Volume 21; doi:10.17073/1609-3577-2018-3-133-145

Abstract:
The structure and electrical properties of (FexOy)10 (ZnO)90 ceramics (0 ≤ x ≤ 3; 1 ≤ y ≤ 4) synthesized in air by one− and two−stage method were studied. To dope ZnO, powders of FeO, α−Fe2O3, and Fe3O4 or a mixture (α−Fe2O3 + FeO) were used. On the basis of X−ray diffraction analysis, gamma−resonance spectroscopy and Raman spectroscopy, it was established that at fixed average iron concentrations of 1—3 at.% in ceramic samples, at least three phases are formed: solid solution Zn1−δFeδO with wurtzite structure and residual iron oxides FexOy, used as doping agents. Scanning electron microscopy and energy−dispersive X−ray analysis have shown that, in the studied ceramics, the grain sizes of the wurtzite phase decreased from several tens of micrometers using one−step synthesis to the submicron level for the case of two−step synthesis. It was found that the incorporation of iron into ZnO leads to a contraction of the crystal lattice in the wurtzite phase and the stronger, the higher the proportion of oxygen in the doping iron oxides FexOy. The study of the temperature dependences of the electrical resistivity have shown that deep donor centers with an activation energy of about 0.35 eV are formed in the wurtzite phase Zn1−δFeδO. The temperature dependences of the electrical resistivity in the undoped ZnO in the temperature range of 6—300 K and in the doped ceramics (FexOy)10(ZnO)90, obtained by the one−step synthesis method, at temperatures below 50 K, are characterized by a variable activation energy, which indicates a strong disordering of their structure.
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