16 results on '"A. Yu. Lashkov"'
Search Results
2. Preparation of Single-Crystal Isotopically Enriched 70Ge by a Hydride Method
- Author
-
V. A. Gavva, O. Yu. Troshin, S. A. Adamchik, A. Yu. Lashkov, N. V. Abrosimov, A. M. Gibin, P. A. Otopkova, A. Yu. Sozin, and A. D. Bulanov
- Subjects
Inorganic Chemistry ,General Chemical Engineering ,Materials Chemistry ,Metals and Alloys - Published
- 2022
3. Thermal Structure of the Filtration Combustion Wave of CаH2 in a Flow of a SiF4 + H2 Mixture
- Author
-
A. Yu. Lashkov, O. Yu. Troshin, and A. D. Bulanov
- Subjects
Calcium hydride ,Hydrogen ,General Chemical Engineering ,chemistry.chemical_element ,General Chemistry ,Mechanics ,Wake ,Combustion ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Thermal ,Silicon tetrafluoride ,Head (vessel) ,Filtration - Abstract
The head and wake waves of filtration combustion of calcium hydride in a flow of a mixture of silicon tetrafluoride and hydrogen at silicon tetrafluoride weight fractions of 0.8, 0.85, 0.9, and 0.98 were studied. The spatial profiles of the combustion waves were constructed. With their aid, the thermal structure of the head and wake waves was found, and the width of each zone in the combustion wave for different compositions of the gas phase was determined. With increasing concentration of the reagent gas in the flow, the reaction zone width increases in the head wave and decreases in the wake wave. The structure of the head wave corresponds to the intermediate combustion wave, and the structure of the wake wave, to the normal combustion wave.
- Published
- 2021
4. An Effect of the Reagent Concentration in the Flow of a Gas Mixture on the Parameters of the Combustion Wave of CaH2 in SiF4
- Author
-
O. Yu. Troshin, A. D. Bulanov, and A. Yu. Lashkov
- Subjects
Exothermic reaction ,Chemistry ,Wave propagation ,General Chemical Engineering ,Thermodynamics ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Combustion ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Reagent ,Silicon tetrafluoride ,Mass concentration (chemistry) ,Physics::Chemical Physics ,0210 nano-technology ,Porous medium ,Mass fraction - Abstract
The dependence has been investigated of the maximum temperature in the reaction front, the linear velocity of the combustion wave of CaH2 in a mixture of gases SiF4 and H2 with the formation of SiH4, and the conversion of calcium hydride on the initial mass concentration of silicon tetrafluoride. The experimental data have been obtained in a vertical flow reactor with forced gas filtration in the range of SiF4 mass fractions of 0.7–0.98. The results of the experiment have been compared with the data of calculation according to the classical physical and mathematical model of the exothermic reaction wave propagation in a porous medium during gas blowing. The similarities and differences have been established between the experimental and calculated values of the maximum temperature in the reaction front, the linear velocity of the combustion wave propagation, and the conversion of the solid-phase reagent.
- Published
- 2021
5. Isotope analysis of highly enriched 'silicon-28' by high-resolution inductively coupled plasma mass spectrometry using an internal standard
- Author
-
A. Yu. Lashkov, A. D. Bulanov, A. I. Suchkov, A. M. Potapov, P. A. Otopkova, Program of Fundamental Scientific Research of Governmental Academies of Sciences for 2019-2021, topic No. 0095-2019-0001., and Программа фундаментальных научных исследований государственных академий наук на 2019-2021 годы № темы 0095-2019-0001
- Subjects
Matrix (chemical analysis) ,Isotope ,Silicon ,chemistry ,Stable isotope ratio ,Analytical chemistry ,chemistry.chemical_element ,Isotopes of silicon ,Inductively coupled plasma ,Mass spectrometry ,Inductively coupled plasma mass spectrometry ,Analytical Chemistry - Abstract
In order to study the isotopic effects in semiconductor materials, single crystals of high chemical and isotopic purity are required. The reliability of the obtained data on the magnitude and the direction of isotopic shifts depends on the accuracy of determining the concentration of all stable isotopes. In the isotopic analysis of enriched “silicon-28” with a high degree of enrichment ( 99.99%), it is necessary to determine the impurities of 29Si and 30Si isotopes at the level of 10-3 ¸ 10-5 at. %. At this concentration level, these isotopes can be considered as impurities. It is difficult to achieve high measurement accuracy with simultaneous registration of the main and “impurity” isotopes in such a wide range of concentrations. The registration of analytical signals of silicon isotopes must be carried out in the solutions with different matrix concentrations. The use of the solutions with the high concentration of the matrix element requires the introduction of corrections for matrix noise and the drift of the instrument sensitivity during the measurement. It is possible to reduce the influence of the irreversible non-spectral interference and sensitivity drift by using the method of internal standardization. The inconsistency of the literature data on the selection criteria for the internal standard required studying the behavior of the signals of the “candidates for the internal standard” for the ELEMENT 2 single-collector high-resolution inductively coupled plasma mass spectrometer on the matrix element concentration and the nature of the solvent, as well as on the solution nebulizing time. Accounting for the irreversible non-spectral matrix noise and instrumental drift in isotopic analysis of enriched “silicon-28” and initial 28SiF4 by inductively coupled plasma mass spectrometry had allowed us to reduce by 3-5 times the random component and by more than an order of magnitude the systematic component of the measurement error in comparison with the external standard method. This made it possible to carry out, with sufficient accuracy, the operational control of the isotopic composition of enriched “silicon-28”, both in the form of silicon tetrafluoride and polycrystalline silicon obtained from it, using a single serial device in the range of isotopic concentrations 0.0001–99.999%.Key words: high-resolution inductively coupled plasma mass spectrometry, isotope analysis, isotopically enriched silicon, internal standard DOI: http://dx.doi.org/10.15826/analitika.2021.25.2.009P.A. Otopkova, A.M. Potapov, A.I. Suchkov, A.D. Bulanov, A.Yu. Lashkov G.G. Devyatykh Institute of Chemistry of High-Purity Substances of the Russian Academy of Sciences (IChHPS RAS), 49 Tropinina St., Nizhny Novgorod, 603951, Russian Federation, Для изучения изотопических эффектов в полупроводниковых материалах требуются монокристаллы с высокой химической и изотопной чистотой. Надежность полученных данных о величине и направлении изотопических сдвигов зависит от точности определения концентрации всех стабильных изотопов. При изотопном анализе обогащенного “кремния-28” с высокой степенью обогащения (более 99.99 %) необходимо определять примеси изотопов 29Si и 30Si на уровне 10-3 ¸ 10-5 ат. %. На таком уровне концентраций указанные изотопы можно рассматривать как примеси. Достижение высокой точности измерений при одновременной регистрации основного и “примесных” изотопов в таком широком интервале концентраций затруднительно. Регистрацию аналитических сигналов изотопов кремния приходится проводить на растворах с разной концентрацией матрицы. Использование растворов с высокой концентрацией матричного элемента требует введения поправок на матричные помехи и дрейф чувствительности прибора в процессе измерения. Снизить влияние необратимых неспектральных помех и дрейфа чувствительности можно при использовании метода внутренней стандартизации. Противоречивость литературных данных о критериях выбора внутреннего стандарта потребовала исследования поведения сигналов элементов “кандидатов во внутренний стандарт“ для одноколлекторного масс-спектрометра высокого разрешения с индуктивно связанной плазмой ELEMENT 2 от концентрации матричного элемента и природы растворителя, а также от времени распыления раствора. Учет необратимых неспектральных матричных помех и аппаратного дрейфа при изотопном анализе обогащенного “кремния-28” и исходного 28SiF4 методом масс-спектрометрии с индуктивно связанной плазмой позволил снизить в 3-5 раз случайную составляющую и более чем на порядок систематическую составляющую погрешности измерения по сравнению с методом внешнего стандарта. Это позволило проводить с достаточной точностью оперативный контроль изотопного состава обогащенного “кремния-28”, как в виде тетрафторида кремния, так и получаемого из него поликристаллического кремния с помощью одного серийного прибора в интервале изотопных концентраций 0.0001–99.999 ат. %.Ключевые слова: масс-спектрометрия высокого разрешения с индуктивно связанной плазмой, изотопный анализ, изотопнообогащенный кремний, внутренний стандартDOI: http://dx.doi.org/10.15826/analitika.2021.25.2.009
- Published
- 2021
6. Isotopic Analysis of Highly Enriched Crystalline 28Si and Initial 28SiF4 by High-Resolution Inductively Coupled Plasma Mass Spectrometry
- Author
-
A. E. Kurganova, A. I. Suchkov, A. D. Bulanov, A. Yu. Lashkov, P. A. Otopkova, and A. M. Potapov
- Subjects
Isotope ,Chemistry ,Orders of magnitude (temperature) ,010401 analytical chemistry ,Analytical chemistry ,Isotope dilution ,010402 general chemistry ,Mass spectrometry ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Impurity ,Inductively coupled plasma ,Inductively coupled plasma mass spectrometry ,Isotope analysis - Abstract
A procedure is described for determining the isotopic composition of highly enriched silicon as elementary 28Si and initial 28SiF4 by a single collector double focusing sector field ICP MS over a wide range of isotope concentrations (more than 6 orders of magnitude). To expand the range of measured isotopic concentrations, the signals of the main and “impurity” isotopes were recorded in solutions of different concentrations. The determination of the matrix effects and mass discrimination factors was carried out using the isotopic dilution method. This procedure allowed us to reach the uncertainty of measuring the concentration of the main isotope of ten thousandths of a percent in enriching >99.999% on a high-resolution single-collector inductively coupled plasma mass spectrometer.
- Published
- 2019
7. Sources of Carbon Impurities in the Preparation of High-Purity Monoisotopic 28Si by a Hydride Method
- Author
-
O. Yu. Troshin, L. V. Shabarova, A. Yu. Sozin, T.V. Kotereva, V. A. Gavva, A. Yu. Lashkov, A. D. Bulanov, T. G. Sorochkina, Yu. P. Kirillov, M. F. Churbanov, Nickolay Abrosimov, and O. Yu. Chernova
- Subjects
010302 applied physics ,Calcium hydride ,Materials science ,Silicon ,Hydride ,General Chemical Engineering ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,engineering.material ,01 natural sciences ,010309 optics ,Inorganic Chemistry ,chemistry.chemical_compound ,Polycrystalline silicon ,chemistry ,Impurity ,0103 physical sciences ,Materials Chemistry ,engineering ,Monoisotopic mass ,Pyrolysis ,Carbon - Abstract
This paper examines sources of carbon impurities in polycrystalline monoisotopic 28Si prepared by a hydride method. Analytical data on the concentrations of carbon-containing impurities in volatile silicon compounds (28SiH4 and 28SiH4), process gases (Ar and H2), and polycrystalline 28Si are used to identify the major sources of carbon in the polycrystalline 28Si prepared by the hydride method. These are the starting 28SiH4 and calcium hydride used in 28SiH4 conversion into 28SiH4. The rate of carbon intake into polycrystalline silicon from the apparatus material during the monosilane pyrolysis process does not exceed 9 × 1011 cm–2 h–1. Polycrystalline silicon has been precipitated from monosilane with different concentrations of hydrocarbon impurities. At hydrocarbon concentrations in the range 10–4 to 10–3 mol %, the carbon concentration in the monosilane correlates with that in the silicon obtained from it. High-purity monosilane has been used to prepare polycrystalline 28Si samples with concentrations of carbon impurities in the range (0.8–2.3) × 1015 cm–3. Based on calculations of the carbon impurity distribution along the length of a zone-refined ingot, we examine the effect of the initial carbon concentration in the starting polycrystal on the yield of single-crystal monoisotopic 28Si. Requirements are formulated for the carbon concentration in polycrystalline 28Si which ensure a high yield of single crystals with parameters suitable for metrological applications.
- Published
- 2018
8. FILTRATION COMBUSTION OF SiF4 AND CaH2 IN VERTICAL FLOW REACTOR
- Author
-
A. Yu. Lashkov, A. D. Bulanov, and O. Yu. Troshin
- Published
- 2019
- Full Text
- View/download PDF
9. Filtration combustion of silicon tetrafluoride and calcium hydride for the preparation of monosilane
- Author
-
A. Yu. Lashkov, O. Yu. Troshin, and A. D. Bulanov
- Subjects
Calcium hydride ,Order of reaction ,General Chemical Engineering ,Inorganic chemistry ,Metals and Alloys ,02 engineering and technology ,Activation energy ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Kinetic energy ,Combustion ,01 natural sciences ,0104 chemical sciences ,law.invention ,Inorganic Chemistry ,chemistry.chemical_compound ,Reaction rate constant ,chemistry ,law ,Materials Chemistry ,Silicon tetrafluoride ,0210 nano-technology ,Filtration - Abstract
We have studied reaction between silicon tetrafluoride and calcium hydride in a vertical flow reactor, which proceeds as combustion in filtration mode. The principal kinetic characteristics of the reaction between SiF4 and CaH2 in a counterpropagating wave have been determined: reaction order n = 1, rate constant k = 0.38 ± 0.05 s–1, and activation energy Ea = 17 ± 2 kJ/mol.
- Published
- 2016
10. Monogermanes 74GeH4 and 73GeH4 of high isotopic and chemical purity
- Author
-
O. Yu. Troshin, M. F. Churbanov, A. V. Gusev, A. Yu. Lashkov, A. D. Bulanov, S. A. Adamchik, and V. A. Lipskii
- Subjects
Chemistry ,Radiochemistry ,General Chemistry ,Chemical purity - Published
- 2014
11. Mechanically activated synthesis of monosilane by the reaction of calcium hydride with silicon tetrafluoride
- Author
-
A. D. Bulanov, V. S. Mikheev, O. Yu. Troshin, and A. Yu. Lashkov
- Subjects
chemistry.chemical_compound ,Calcium hydride ,Chemistry ,General Chemical Engineering ,Inorganic chemistry ,Silicon tetrafluoride ,General Chemistry ,Grinding - Abstract
Possibility of performing a mechanically activated synthesis of pure monosilane by the reaction of calcium hydride with silicon tetrafluoride in a rotating flow-through reactor containing milling bodies was analyzed. A number of operation parameters of the grinding reactor were theoretically evaluated and experimentally determined.
- Published
- 2010
12. Reaction of silicon tetrafluoride with calcium hydride as a propagating wave
- Author
-
A. Yu. Lashkov, O. Yu. Troshin, A. D. Bulanov, and V. S. Mikheev
- Subjects
Exothermic reaction ,Calcium hydride ,Physics::Instrumentation and Detectors ,Wave propagation ,Materials Science (miscellaneous) ,Inorganic chemistry ,chemistry.chemical_element ,Calcium ,Silane ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Scientific method ,Silicon tetrafluoride ,Physics::Chemical Physics ,Physical and Theoretical Chemistry ,Porous medium - Abstract
The synthesis of silane by reacting silicon tetrafluoride and calcium hydride is shown to proceed as a propagating wave. The main parameters of the process, namely, the propagation velocity, the reaction front temperature, and calcium conversion, are determined. The mathematical model of wave propagation for an exothermic reaction in a porous medium with purging a gaseous oxidant describes qualitatively the major laws of the process.
- Published
- 2008
13. Production of germanium stable isotopes single crystals
- Author
-
Oleg Troshin, Mihail Fedorovich Churbanov, V. A. Gavva, Artem Yu. Lashkov, A. D. Bulanov, Eugeniy A. Kozyrev, Sergey A. Adamchik, Ivan A. Andryushchenko, Victor A. Lipskii, A. V. Gusev, and N. V. Abrosimov
- Subjects
010302 applied physics ,Materials science ,Isotope ,Stable isotope ratio ,Radiochemistry ,chemistry.chemical_element ,Germanium ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,chemistry ,0103 physical sciences ,General Materials Science ,0210 nano-technology ,Pyrolysis - Published
- 2017
14. C1–C4 hydrocarbon release in the preparation of SiF4 through Na2SiF6 pyrolysis
- Author
-
T. G. Sorochkina, V. A. Krylov, A. D. Bulanov, and A. Yu. Lashkov
- Subjects
chemistry.chemical_classification ,General Chemical Engineering ,Inorganic chemistry ,Thermal decomposition ,Metals and Alloys ,Fraction (chemistry) ,Inorganic Chemistry ,Sodium hexafluorosilicate ,chemistry.chemical_compound ,Hydrocarbon ,chemistry ,Impurity ,Materials Chemistry ,Silicon tetrafluoride ,Sodium carbonate ,Pyrolysis - Abstract
Hydrocarbon impurities in silicon tetrafluoride originate from the sodium hexafluorosilicate used as a precursor for the preparation of SiF4 through the thermal decomposition of Na2SiF6. We have studied the fraction of C1–C4 hydrocarbons released as a function of temperature during the thermal decomposition of sodium hexafluorosilicate. The lighter hydrocarbons—methane, ethane, and ethylene—are shown to be released at lower temperatures. One source of hydrocarbon impurities in sodium hexafluorosilicate is the sodium carbonate used to prepare it.
- Published
- 2011
15. Formation of impurity Si2OH6 in silane synthesized from silicon tetrafluoride
- Author
-
O. Yu. Troshin, A. Yu. Sozin, A. D. Bulanov, Peter Sennikov, and A. Yu. Lashkov
- Subjects
Calcium hydride ,Hydrogen ,Materials Science (miscellaneous) ,Inorganic chemistry ,chemistry.chemical_element ,Silane ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Impurity ,Oxygen contamination ,Silicon tetrafluoride ,Physical and Theoretical Chemistry ,Fluoride - Abstract
The possibility of the reduction of hexafluorodisiloxane by calcium hydride in the synthesis of silane from silicon tetrafluoride has been studied. This reaction is shown to be not decisive for oxygen contamination of silane. The most likely reason for the appearance of impurity Si2OH6 in “fluoride” silane is the Ca(OH)2-catalyzed reaction of silane with trace water. The concentration of impurity Si2OH6 in silane at the stage of synthesis may be efficiently decreased by the preliminary purging of calcium hydride with a hydrogen (grade A) flow.
- Published
- 2011
16. Production of silanes 29SiH4 and 30SiH4 of high chemical and isotopic purity
- Author
-
O. Yu. Troshin, M. F. Churbanov, A. P. Kotkov, A. M. Potapov, A. D. Bulanov, N. D. Grishnova, S. A. Adamchik, and A. Yu. Lashkov
- Subjects
chemistry.chemical_compound ,Silanes ,chemistry ,Organic chemistry ,General Chemistry - Published
- 2010
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.