Materials of Electronics Engineering (E-Journal) / Известия высших учебных заведений. Материалы электронной техники
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О ПРИРОДЕ ТЕРМОАКЦЕПТОРОВ В ОБЛУЧЕННОМ ЭЛЕКТРОНАМИ ВЫСОКООМНОМ КРЕМНИИ
Get PDFThis work is an analysis of the possible role of deep acceptor centers in silicon in the formation of the experimentally observed thermal acceptor effect consisting in the change from n to p conductivity type after annealing of electron or neutron irradiated high resistivity silicon. Based on the solution of the electrical negativity equation for compensated silicon we have estimated the dependence of the concentration of deep acceptor centers that is required for changing to p−type conductivity on acceptor energy level and shallow donor concentration. We show that deep acceptor centers can make a significant contribution to the thermal acceptor effect in high resistivity silicon (energy levels of up to 0.4 eV). The concentrations of deep acceptor centers required for changing the conductivity type are of the order of 1012— 1014 cm−3. These concentrations seem to be achievable in samples containing low shallow donor concentrations (1012—1013 cm−3). Such centers can be divacancy−impurity complexes (Fe, P) with ionization energies of up to 0.34 eV. The thermal activation of interstitial boron is not excluded either.
СТРУКТУРА И МАГНИТНЫЕ СВОЙСТВА ПОРОШКА ГЕКСАФЕРРИТА СТРОНЦИЯ ПОСЛЕ ИЗМЕЛЬЧЕНИЯ В ВОДЕ И ТОЛУОЛЕ С ПОСЛЕДУЮЩИМ ОТЖИГОМ
Get PDFStructural changes of strontium hexaferrite powders after milling in water and toluene and after subsequent annealing were studied using X-ray diffraction, Scanning Electron Microscopy and Laser diffraction. Also magnetic properties changes were studied. The coarse-grain powder milling leads to an abrupt decrease of its particles size and the average crystallite size as well as an increase of SrFe12O19 phase lattice microstrains. Saturation magnetization and remanence decrease after milling in both media. At the same time coercive force of milled powders changes insignificantly with increasing milling time. The subsequent annealing allowed us to increase the magnetic properties of the powder. The annealed powders are characterized by the following magnetic properties: µ0Нci = 0,42¸0,49 T, µ 0Ir = 0,23¸0,24 T, (BH)max = 8-9,6 kJ/m3
ИССЛЕДОВАНИЕ СВОЙСТВ КРУПНОГАБАРИТНЫХ МОНОКРИСТАЛЛОВ АНТИМОНИДА ИНДИЯ, ВЫРАЩЕННЫХ МЕТОДОМ ЧОХРАЛЬСКОГО В КРИСТАЛЛОГРАФИЧЕСКОМ НАПРАВЛЕНИИ [100]
Get PDFInvestigation on the properties of large [100]−oriented InSb single crystals grown by Czoсhralski method The properties of undoped and heavily Te doped large single crystals of InSb grown by Czochralski method in the [100] direction and intended for use in IR photodetectors of new generation were studied. It was found that the non−uniformity in undoped crystals does not exceed 10—16%. The average dislocation density in this ingots was 7 101 cm−2 and their distribution along the diameter of (100)−oriented wafers was much more uniform than for the (211)−oriented wafers. We also studied the microstructure of heavily Te doped InSb crystals. It was established that the dislocation density in these crystals was below 1 102 cm−2. Te doping producing the electron concentration higher than 1,5 ⋅ 1018 cm−3 gave rise to the formation of high density of precipitates. The optical transmission of the samples with electron concentration ~6,9 ⋅ 1017 cm−3 was found to de higher 40 % for the wavelength range of 3—5 µ
ПЕРСПЕКТИВНЫЕ МАТЕРИАЛЫ АКУСТОЭЛЕКТРОНИКИ
Get PDFMulticomponent piezoelectric crystals of langasite family were studied. The process of crystal growth and crystal structure were investigated. X−ray diffraction and topography were used to study the acoustic properties of crystals. The possibility of application of the piezoelectric crystals in high−temperature SAW−sensors was demonstrated.Представлены результаты исследования многокомпонентных пьезоэлектрических кристаллов группы лантангаллиевого силиката (лангасита). Изучены процессы синтеза и структура кристаллов. С использованием методов рентгеновской топографии и дифрактометрии исследованы акустические свойствакристаллов. Продемонстрирована возможность применения этих пьезоэлектрических кристаллов ввысокотемпературных сенсорных устройствах на поверхностных акустических волнах
СВОЙСТВА ПОРИСТЫХ ПЛЕНОЧНЫХ СТРУКТУР Si–КВАНТОВЫЕ ТОЧКИ/SiOx, ПОЛУЧЕННЫХ ПО ФТОРОВОДОРОДНОЙ ТЕХНОЛОГИИ
Get PDFA detailed study of Si quantum dots/SiOx film structures synthesized using a new hydrofluoric technology of forming silicon nanoparticles in porous silicon oxide matrices has been performed. A physical mechanism of the effect of chemical treatment in HF vapors in air on the structural and luminescent properties of the film porous systems with nanosized silicon has been suggested. We show that the passivation of the broken bonds on the surface of Si nanoinclusions as a result of the treatment occurs with the participation of oxygen, fluorine and hydrogen atoms, and this effect depletes the nonradiative recombination channel by two orders of magnitude. We suggest a model explaining the blue shift of the photoluminescence spectra as a result of the treatment due to a decrease in the sizes of the Si−QD during the oxidation of their surface layers. Проведено детальное исследование пленочных структур Si−квантовые точки/SiOx, полученных по новой фтороводородной технологии формирования наночастиц кремния в пористой матрице оксида кремния. Предложен физический механизм влияния химической обработки в парах HF на воздухе на структурные и свето- излучающие свойства пленочных пористых систем с наноразмерным кремнием. Показано, что пассивация оборванных связей на поверхности Si−нановключений в результате обработки происходит при участии атомов кислорода, фтора и водорода, что на два порядка величины ослабляет безызлучательный канал рекомбинации. Предложена модель, объясняющая сдвиг спектра фотолюминесценции в область голубого свечения в результате обработки вследствие уменьшения размеров Si−квантовых точек при окислении их поверхностного слоя
ИССЛЕДОВАНИЕ ВОЗМОЖНОСТИ ПОЛУЧЕНИЯ ФЕРРИТА МАРКИ 2000НМ ПО КОРОТКОЙ ТЕХНОЛОГИЧЕСКОЙ СХЕМЕ
Get PDFThe possibility of obtaining Mn—Zn-ferrite 2000 NM on the short process flow, which differs from the usual lack of diffusion operations roasting and grinding. It is shown that the use of the basic composition in sintering processes develop secondary recrystallization and zonal isolation, leading to the formation of highly inhomogeneous microstructure obtained with low values of the magnetic permeability. A homogeneous microstructure characteristic recrystallization, managed by doping copper oxide and zinc. By doping CuO permeability far from the desired value, but its temperature coefficient is small. By doping ZnO reached the desired value of magnetic permeability, but dramatically increases its temperature coefficient.The optimum combination of the magnetic parameters obtained in complex copper oxides doped ferrite and zinc.Рассмотрена возможность получения Mn—Zn-феррита марки 2000 НМ по короткой технологической схеме, отличающейся от традиционной отсутствием операций диффузионного обжига и измельчения. Показано, что при использовании базового состава при спекании развиваются процессы вторичной рекристаллизации и зонального обособления, приводящие к формированию резко неоднородной микроструктуры. При этом получены низкие значения магнитной проницаемости. Однородную микроструктуру, характерную для собирательной рекристаллизации, наблюдали при легировании оксидами меди и цинка. Оптимальное сочетание магнитных параметров достигнуто при комплексном легировании феррита оксидами меди и цинка
ИЗУЧЕНИЕ ЭЛЕКТРОФИЗИЧЕСКИХ СВОЙСТВ ДИОДОВ ШОТКИ, ИЗГОТОВЛЕННЫХ НА ОСНОВЕ КРЕМНИЯ С РАЗЛИЧНЫМИ МЕТАЛЛИЧЕСКИМИ СЛОЯМИ
Get PDFWe have investigated the fabrication of AuxTi100−x—nSi (where x is 10; 36; 87) and PbxSb100−x—nSi (where x = 52; 70; 87) Schottky diodes and the electrical properties of AuxTi100−x—nSi (where x = 10; 36; 87) and PbxSb100−x—nSi (where x = 52; 70; 87)Schottky diodes. The Au36Ti64, Pb52Sb48 alloy film has an amorphous structure, while the other films are polycrystalline. We have determined Schottky barrier height dependingon the composition and structure of the metal films and found that the barrier height is quite sensitive to the composition of the metal alloy. We show that the electrical properties of the AuxTi100−x—nS and PbxSb100−x—nSi Schottky diodes depend on the composition and structure of the metal films.Исследовано получение и изучены электрофизические свойства AuxTi100−x—nSi (где х = 10, 36, 87) и PbxSb100−x—nSi (где х = 52, 70, 87) диодов Шотки. Установлено, что пленки сплавов Au36Ti64 и Pb52Sb48 имеют аморфную структуру, а остальные пленки — поликристаллическую. Определена высота барьера диодов Шотки в зависимости от состава и структуры пленок металла. Выявлено, что электрофизические свойства AuxTi100−x—nS и PbxSb100−x—nSi диодов Шотки зависят от состава и структуры пленок металла
НИТРИДНЫЕ НЕМТ ПРОТИВ АРСЕНИДНЫХ: ПОСЛЕДНЯЯ БИТВА?
Get PDFIn this paper, we have studied the limitcapabilities of nitride and arsenide HEMTs and shown that the frequency limit of these devices has already been reached. The nature of these frequency constraints arise from device design rather than from semiconduc- tor properties. In particular we have established that the product tBCdg is the critical parameter which could not be minimized any further technologically. In summary it could be stated that nowadays InP pHEMTs offer the highest frequencies and GaN HEMTs on SiC substrate are the most powerful devices. In addition we have shown that the breakdown voltages and power density of nitride HEMTs at a given operating frequency are controlled by heterostructure barrier layer thickness, increasing with decrease of the latter. Therefore it is necessary to develop high efficiency nitride nanoheterostructures with tB less than 10 nm. In this respect the AlN/GaN heterostructures are beyond comparison due to the good performance of 2D gas and relative simplicity of growth process.
МЕЛКОДИСПЕРСНЫЕ ЧАСТИЦЫ МЕТИЛСИЛСЕСКВИОКСАНОВ С ФРАГМЕНТАМИ SiO4/2 В СТРУКТУРЕ
Get PDFThe results of structural and morphological investigations of methylsilsesquioxane finely divided particles synthesized by hydrolytical co-condensation of methyltrichlorosilane and tetrachlorous silicon alcocksilined «in situ» are presented. The silica-type hydrophobe particles were obtained using above mentioned method with the result of 98.7—99.4 % (mass) compared to load. These particles were identified as crystalline formations with lattice period of 5.5—8.0 nm and inter-planery distance 0.92—1.04 nm in near order. It is shown that in contrast to well-known crystalline methylsilsesquioxanes introduction of chemically bonded SiO4/2 fragments in material structure leads to formation of 2—3 micrometer-size spherical particles from primarily existed 10—15 nm particles; these namely particles are responsible for spherical surface morphology. The method of extraction of siloxane nano-particles (2.5—280 nm) from products of reaction was described; the behavior of particles in suspension was studied and particle dimensional parameters were determined with the help of helium−neon 0.6328 nm laser correlation spectroscopy