Materials of Electronics Engineering (E-Journal) / Известия высших учебных заведений. Материалы электронной техники
Not a member yet
466 research outputs found
Sort by
ФОРМИРОВАНИЕ ЗАРЯДОВЫХ НАСОСОВ В СТРУКТУРЕ ФОТОПРЕОБРАЗОВАТЕЛЕЙ
Get PDFResults of further investigation into original concept of charge pumps in the structure of photoelectric cells show that charge pumps are formed due to the formation of spatial defect−dopant complexes which produce a qualitative change in the transport mechanism of light generated charges at the base of the solar cell. For the first time a large scale charge pump manufacturing process has been offered. This process involves a non−thermal or «cold» photon annealing and uses standard photon annealing equipment. The photon annealing effect is achieved by using an original photomask (removable). The mask provides an annealing pattern with multiple light sources and heat insulation of the target wafer. This process is called local photon annealing (LPA). Due to its efficiency and simplicity the process does not require significant industrial investment. Experimental results show that it is possible to increase short circuit current and maximum power output of a solar cell with the use of the LPA technique. Experimental solar cell samples have been chosen from different manufacturers.
ОСОБЕННОСТИ ВЫРАЩИВАНИЯ НИЗКОДИСЛОКАЦИОННЫХ КРИСТАЛЛОВ ГЕРМАНИЯ БОЛЬШОГО ДИАМЕТРА МЕТОДОМ ЧОХРАЛЬСКОГО
Get PDFCz growth of large diameter Ge single crystals has been studied. The crystals have been grown from the melt with various shapes of the crystallization front. The formation of dislocation low angle boundaries (LAB) has been analyzed. We have analyzed the formation of LAB in the as−grown Ge crystals taking into account the actual distribution of thermal tension in the crystal in the presence of radial and axial heat sinks. The behavior LAB−forming dislocations in the thermal tension field has been considered. We have analyzed the migration of these dislocations in the sliding planes and specified possible dislocation aggregation planes. The best results have been obtained for crystals in which the crystallization front was slightly concave towards the crystal. Thus, we have observed a uniform distribution of dislocations. As a result of the analysis we have determined the thermal conditions for growth of LAB free ingots. Experiments confirmed the compliance of model representations with real crystal growth conditions, and we have obtained Ge single crystals with a diameter of100 mmand more, with a low dislocations density and free from LAB
ИССЛЕДОВАНИЕ ФАЗОВОГО И ПРИМЕСНОГО СОСТАВА ЛЕНТ КАТОДНЫХ СПЛАВОВ Pd—Ba и Pt—Ba
Get PDFWe have studied the phase and impurity composition of Pd—Ba and Pt—Ba cathode alloys obtained on an A 535.02TO arc melting plant using a technology developed by AO Shokin NPP Istok. The study showed that the concentration of detrimental impurities (C; Zn; Cu; Al) in the specimens is within the allowed range. Pd—Ba tapes are rich in Ba but this does not compromise their quality. We have confirmed the earlier found domination of two−phase composition in Pd—Ba and Pt—Ba alloys where one of the phase is an intermetallic compound (Pd5Ba, Pt5Ba) and the other is a noble metal(the matrix). The intermetallide is distributed in the platinum metal matrix quite inhomogeneously, this tangibly impairing the operation parameters of cathodes produced from these alloys. For the first time we have shown the high efficiency of transmission electron microscopy for studying Pd—Ba and Pt—Ba cathode alloys. We have for the first time found the Pd2О phase in Pd—Ba. It may significantly reduce the secondary electron emission coefficient and the quality of devices based on this alloy. We have determined the Pd and Pd5Ba grain size in the Pd—Ba alloys and the Pt and Pt5Ba grain size in the Pt—Ba alloys. All the Pd and Pt5Ba grains contain high densities of randomly arranged dislocations, and Pt5Ba grains contain internal stresses. Recommendations have been given concerning the improvement of the current Pd—Ba and Pt—Ba cathode alloy tape technology
РЕШЕНИЕ X КОНФЕРЕНЦИИ ПО АКТУАЛЬНЫМ ПРОБЛЕМАМ ФИЗИКИ, МАТЕРИАЛОВЕДЕНИЯ, ТЕХНОЛОГИИ И ДИАГНОСТИКИ КРЕМНИЯ, НАНОРАЗМЕРНЫХ СТРУКТУР И ПРИБОРОВ НА ЕГО ОСНОВЕ («КРЕМНИЙ−2014»)
Get PDFВлияние отжига на недиагональный магнитоимпеданс в аморфных проводах
Get PDFMagnetoimpedance (MI) effect in amorphous ferromagnetic microwires represents is the ideal base for sensing technology and is currently used to develop high sensitive sensors of weak magnetic fields with a resolution up to few micro−Oersteds. The effect of heat treatment on off−diagonal MI in glass coated ferromagnetic amorphous microwires has been studied in order to improve MI sensitivity and temperature stability. We have shown the dependence of sensor signal on temperature. The wires had Co−based composition and internal stress induced helical or circumferential anisotropy. We have demonstrated that annealing of the entire sensing element including the electric contacts and the detection coil may improve the sensitivity of the output signal to an external magnetic field by about 25% and decrease its temperature sensitivity almost twofold in the −30…+80 °C range. These improvements require strict control of the annealing parameters. The best results are obtained for annealing at 160 °C for 2−3 minutes. The experimentally observed changes are related with stress relaxation during annealing; in particular; relaxation of the stresses occurring during solidification due to the difference in the thermal expansion coefficients of the metal core and the glass sheet
ОПТИМИЗАЦИЯ УРОВНЯ ЛЕГИРОВАНИЯ КРЕМНИЯ «СОЛНЕЧНОГО» КАЧЕСТВА ДЛЯ ПОВЫШЕНИЯ ПРИГОДНОГО ОБЪЕМА СЛИТКОВ И КПД СОЛНЕЧНЫХ ЭЛЕМЕНТОВ
Get PDFIn the close future, use of SoG should become prominent for photovoltaic ingot production as it requires much less energy for purification compared to Silicon grades using gas transformation and purification (usually Siemens process or equivalent also used for electronic−grade preparation). During this study, several kinds of silicon were compared with different rates of dopant content (mainly boron and phosphorus). Ingot yield and cell efficiency were optimized for each source of silicon at a production level (450 kg ingots) using boron or gallium doping. Starting from the resistivity specification given by the cell process, the doping level was adjusted in order to maximize the ingot silicon yield (weight of silicon bricks used for wafer cutting/ weight of Silicon ingot). After doping adjustment, ingot quality was checked: brick resistivity, lifetime of minority carriers and wafers were processed into solar cells. Optimizing of doping led to get comparable ingot yields and cell efficiencies using SoG and silicon purified by Siemens process or equivalent. The study was implemented at Kazakhstan Solar Silicon plant in Ust−Kamenogorsk using Kazakhstan SoG, SoG from a European manufacturer and polycrystalline Silicon purified by Siemens process. Directional solidification furnaces were manufactured by the French company ECM Technologies
ОСОБЕННОСТИ ЛЕГИРОВАНИЯ КРЕМНИЯ МЕТОДОМ ТЕРМОМИГРАЦИИ
Get PDFCharacteristics of crystal doping with electrically active impurities by the thermomigration method for two− and three−component liquid zones in comparison with diffusion alloying (for the example of silicon) have been analyzed.We have found that the concentration range of doping for the two− component migration zone is much narrower than the range of diffusion doping. Introduction of a third component into the liquid phase allows extending the range of doping thermomigration to values exceeding the diffusion doping range for the same impurity. For silicon crystals this technological advantage of thermomigration is achieved with the use of three zones, GaxAl1−xSi and SnxAl1−xSi.We show that the speed of crystal doping by the thermomigration method in technologically relevant situations is by orders of magnitude higher than that of diffusion alloying. Thermomigration doped layers with steadily moving liquid zones have higher structural perfection than diffusion doped layers.We show that the thermomigration alloying method can be used in the technology of semiconductor device structures, provided that their planar dimensions and thickness are tens micrometers or more. Quantitative results obtained for the example of liquid zone migration in silicon, but the features of thermomigration as a doping method are true for other semiconductor materials
Задачи оптимизации наноразмерных полупроводниковых гетероструктур
Get PDFIn the paper a new approach to solve the optimization problem of nanoscale semiconductor heterostructures is presented. In this paper the authors formulated and solved The problem of the barrier layer optimal doping is formulated for the case of multilayer barrier. The problem is solved using the effective optimization algorithms based on gradient methods. As an example, is considered heterostructure Al0.25GaN/GaN with the total thickness of the barrier layer 30 nm. Obtained in the computational experiment results are consistent with the modern trend to move from homogeneous doping profile to a planar-doping in the technology of manufacturing fieldeffect transistors. The developed tools of mathematical modeling and optimization can be used in the engineering of field effect transistors. The proposed approach creates the conditions for computer-aided design of such structures.Представлен новый подход, позволяющий решать задачи оптимизации наноразмерных полупроводниковых гетероструктур. Поставлена и решена задача, связанная с определением оптимального легирования барьерного слоя, состоящего из ряда подслоев, который обеспечивает заданную концентрацию электронов в канале проводимости в полупроводниковых гетероструктурах. Для решения поставленной задачи построены эффективные алгоритмы оптимизации, основанные на градиентных методах. В качестве примера рассмотрена гетероструктура Al0,25GaN/GaN с суммарной толщиной барьерного слоя 30 нм. Полученные в ходе вычислительного эксперимента результаты согласуются с современной тенденцией к переходу от однородного профиля легирования к планарному d-легированию в технологиях изготовления полевых транзисторов. Разработанные средства математического моделирования и оптимизации могут применяться в технологиях изготовления полевых транзисторов. Представленные в работе подходы создают условия для автоматизированного проектирования таких структур
Применение радиоактивных изотопов для создания бета−вольтаических генераторов
Get PDFIn this article we have analyzed radioactive isotope applications in the technology of autonomous power supplies and the materials used in radioisotope thermoelectric generators (RTGs), justified the advantage of manufacturing betavoltaic generators, compared them with other electric power sources and considered the mechanism of β−decay and positioned it among other types of nuclear transformations. We have also drawn up the basic radiation safety requirements to the materials used for the hull and the converter, analyzed some earlier designs of radioisotope betavoltaic sources and set up a list of isotopes suitable as energy sources in betavoltaic generators. Furthermore, we have analyzed methods of obtaining radioactive materials which exhibit β−decay, their basic properties and abundance in nature. In conclusion, the choice of nickel−63 isotope has been selected as preferable for betavoltaic generators due to the optimum combination of half−life, average particle energy and radiation intensity.Рассмотрены особенности применения радиоактивных изотопов при создании автономных источников электропитания. Проведен анализ веществ, используемых в радиоизотопных термоэлектрических генераторах. Обоснована перспективность изготовления бета−вольтаических генераторов, представлено сравнение их с другими источниками электрического питания. Рассмотрен механизм β−распада и его место среди других видов ядерных превращений. Сформулированы основные требования по радиационной безопасности, а также требования к применяемым материалам корпуса и преобразователя. Рассмотрены некоторые предложенные ранее конструкции радиоизотопных бета−вольтаических источников. Приведен перечень изотопов, возможных для применения в качестве источника энергии в бета−вольтаическом генераторе. Рассмотрены методы получения радиоактивных материалов, демонстрирующих β−распад, их основные свойства и природные изотопы. Сделан вывод о предпочтительности выбора изотопа никеля−63 для применения в бета−вольтаических генераторах благодаря оптимальному сочетанию времени полураспада, средней энергии частиц и интенсивности излучения