106 research outputs found
Spectral Ellipsometry as a Method of Investigation of Influence of Rapid Thermal Processing of Silicon Wafers on their Optical Characteristics
One of the possible ways of improvement of the surface properties of silicon is the solid phase recrystallization of the surface silicon layer after the chemical-mechanical polishing with application of the rapid thermal treatment with the pulses of second duration. The purpose of the given paper is investigation of influence of the rapid thermal treatment of the initial silicon wafers of the various doping level and reticular density on their optical characteristics by means of the spectral ellipsometry method. The investigation results are presented by means of the spectral ellipsometry method of the rapid thermal processing influence on the initial silicon wafers (KDB12 orientation , KDB10 orientation and KDB0.005 orientation ) of the various level of doping and reticular density influence on their optical characteristics: refraction and absorption ratios. Influence was confirmed of the silicon reticular density on its optical characteristics before and after the rapid thermal processing. It was shown, that reduction of the refraction and absorption ratios in the center of the Brillouin zone for the silicon samples with the high Boron concentration after the rapid thermal processing as compared with the low doped silicon. In the area of the maximum absorption peak, corresponding to the energy of the electron exit from the silicon surface (4.34 eV) the refraction indicator of the high doped silicon becomes higher, than of the low doped silicon, which is determined by the high concentration of the vacant charge carriers on the silicon surface in this spectral range. It was established, that the spectral area 3.59–4.67 eV, corresponding to the work of the electrons, exiting the silicon surface, the most informative way shows the difference of the 3 optical parameters of silicon of the different orientation, and for evaluation of influence of the silicon doping level on its optical characteristics the most informative is the spectral range of 3.32–4.34 eV
Спектральная эллипсометрия как метод изучения влияния быстрой термообработки кремниевых пластин на их оптические характеристики
One of the possible ways of improvement of the surface properties of silicon is the solid phase recrystallization of the surface silicon layer after the chemical-mechanical polishing with application of the rapid thermal treatment with the pulses of second duration. The purpose of the given paper is investigation of influence of the rapid thermal treatment of the initial silicon wafers of the various doping level and reticular density on their optical characteristics by means of the spectral ellipsometry method.The investigation results are presented by means of the spectral ellipsometry method of the rapid thermal processing influence on the initial silicon wafers (KDB12 orientation <100>, KDB10 orientation <111> and KDB0.005 orientation <100>) of the various level of doping and reticular density influence on their optical characteristics: refraction and absorption ratios. Influence was confirmed of the silicon reticular density on its optical characteristics before and after the rapid thermal processing. It was shown, that reduction of the refraction and absorption ratios in the center of the Brillouin zone for the silicon samples with the high Boron concentration after the rapid thermal processing as compared with the low doped silicon. In the area of the maximum absorption peak, corresponding to the energy of the electron exit from the silicon surface (4.34 eV) the refraction indicator of the high doped silicon becomes higher, than of the low doped silicon, which is determined by the high concentration of the vacant charge carriers on the silicon surface in this spectral range.It was established, that the spectral area 3.59–4.67 eV, corresponding to the work of the electrons, exiting the silicon surface, the most informative way shows the difference of the 3 optical parameters of silicon of the different orientation, and for evaluation of influence of the silicon doping level on its optical characteristics the most informative is the spectral range of 3.32–4.34 eV. Одним из возможных путей улучшения поверхностных свойств кремния является твердофазная рекристаллизация поверхностного слоя кремния после химико-механической полировки с использованием быстрой термической обработки импульсами секундной длительности. Целью данной работы являлось исследование влияния быстрой термической обработки исходных кремниевых пластин различного уровня легирования и ретикулярной плотности на их оптические характеристики методом спектральной эллипсометрии.Приведены результаты исследования методом спектральной эллипсометрии влияния быстрой термообработки исходных кремниевых пластин (КДБ-12 ориентации <100>, КДБ-10 ориентации<111> и КДБ-0,005 ориентации <100>) различного уровня легирования и ретикулярной плотности на их оптические характеристики: коэффициенты преломления, поглощения. Подтверждено влияние ретикулярной плотности кремния на его оптические характеристики до и после быстрой термообработки. Установлено уменьшение коэффициентов преломления и поглощения в центре зоны Бриллюэна для образцов кремния с высокой концентрацией бора после быстрой термообработки по сравнению с низколегированным кремнием. В области пика максимума поглощения, соответствующего энергии выхода электрона с поверхности кремния (4.34 эВ) показатель преломления высоколегированного кремния становится выше, чем у низколегированного кремния, что обусловлено высокой концентрацией свободных носителей заряда на поверхности кремния в этом спектральном диапазоне.Установлено, что спектральная область 3.59–4.67 эВ, соответствующая работе выхода электронов с поверхности кремния, наиболее информативно показывает различие оптических параметров кремния различной ориентации, а для оценки влияния уровня легирования кремния на его оптические характеристики наиболее информативен спектральный диапазон 3.32–4.34 эВ
ВЛИЯНИЕ БЫСТРОЙ ТЕРМИЧЕСКОЙ ОБРАБОТКИ ПОДЗАТВОРНОГО ДИЭЛЕКТРИКА НА ПАРАМЕТРЫ МОЩНЫХ ПОЛЕВЫХ МОSFЕТ ТРАНЗИСТОРОВ
Приведены результаты исследований влияния быстрой термической обработки подзатворного диэлектрика на параметры мощных p - и n -канальных MOSFET транзисторов. Установлено, что данная обработка позволяет за счет улучшения зарядовых и структурных свойств диэлектрика уменьшить токи утечки затвора и повысить надежность приборов
Common conformational changes induced in type 2 picornavirus IRESs by cognate trans-acting factors
Type 2 internal ribosomal entry sites (IRESs) of encephalomyocarditis virus (EMCV), foot-and-mouth disease virus (FMDV) and other picornaviruses comprise five major domains H-L. Initiation of translation on these IRESs begins with specific binding of the central domain of initiation factor, eIF4G to the J-K domains, which is stimulated by eIF4A. eIF4G/eIF4A then restructure the region of ribosomal attachment on the IRES and promote recruitment of ribosomal 43S pre-initiation complexes. In addition to canonical translation factors, type 2 IRESs also require IRES trans-acting factors (ITAFs) that are hypothesized to stabilize the optimal IRES conformation that supports efficient ribosomal recruitment: the EMCV IRES is stimulated by pyrimidine tract binding protein (PTB), whereas the FMDV IRES requires PTB and ITAF45. To test this hypothesis, we assessed the effect of ITAFs on the conformations of EMCV and FMDV IRESs by comparing their influence on hydroxyl radical cleavage of these IRESs from the central domain of eIF4G. The observed changes in cleavage patterns suggest that cognate ITAFs promote similar conformational changes that are consistent with adoption by the IRESs of comparable, more compact structures, in which domain J undergoes local conformational changes and is brought into closer proximity to the base of domain I
The detection of neutrino interactions in the emulsion/lead target of the OPERA experiment
The OPERA neutrino detector in the underground Gran Sasso Laboratory (LNGS)
was designed to perform the first detection of neutrino oscillations in
appearance mode through the study of oscillations. The
apparatus consists of an emulsion/lead target complemented by electronic
detectors and it is placed in the high energy long-baseline CERN to LNGS beam
(CNGS) 730 km away from the neutrino source. Runs with CNGS neutrinos were
successfully carried out in 2007 and 2008 with the detector fully operational
with its related facilities for the emulsion handling and analysis. After a
brief description of the beam and of the experimental setup we report on the
collection, reconstruction and analysis procedures of first samples of neutrino
interaction events
First events from the CNGS neutrino beam detected in the OPERA experiment
The OPERA neutrino detector at the underground Gran Sasso Laboratory (LNGS)
was designed to perform the first detection of neutrino oscillations in
appearance mode, through the study of nu_mu to nu_tau oscillations. The
apparatus consists of a lead/emulsion-film target complemented by electronic
detectors. It is placed in the high-energy, long-baseline CERN to LNGS beam
(CNGS) 730 km away from the neutrino source. In August 2006 a first run with
CNGS neutrinos was successfully conducted. A first sample of neutrino events
was collected, statistically consistent with the integrated beam intensity.
After a brief description of the beam and of the various sub-detectors, we
report on the achievement of this milestone, presenting the first data and some
analysis results.Comment: Submitted to the New Journal of Physic
Emulsion sheet doublets as interface trackers for the OPERA experiment
New methods for efficient and unambiguous interconnection between electronic
counters and target units based on nuclear photographic emulsion films have
been developed. The application to the OPERA experiment, that aims at detecting
oscillations between mu neutrino and tau neutrino in the CNGS neutrino beam, is
reported in this paper. In order to reduce background due to latent tracks
collected before installation in the detector, on-site large-scale treatments
of the emulsions ("refreshing") have been applied. Changeable Sheet (CSd)
packages, each made of a doublet of emulsion films, have been designed,
assembled and coupled to the OPERA target units ("ECC bricks"). A device has
been built to print X-ray spots for accurate interconnection both within the
CSd and between the CSd and the related ECC brick. Sample emulsion films have
been extensively scanned with state-of-the-art automated optical microscopes.
Efficient track-matching and powerful background rejection have been achieved
in tests with electronically tagged penetrating muons. Further improvement of
in-doublet film alignment was obtained by matching the pattern of low-energy
electron tracks. The commissioning of the overall OPERA alignment procedure is
in progress.Comment: 19 pages, 19 figure
Measurement of the atmospheric muon charge ratio with the OPERA detector
The OPERA detector at the Gran Sasso underground laboratory (LNGS) was used
to measure the atmospheric muon charge ratio in the TeV energy region. We
analyzed 403069 atmospheric muons corresponding to 113.4 days of livetime
during the 2008 CNGS run. We computed separately the muon charge ratio for
single and for multiple muon events in order to select different energy regions
of the primary cosmic ray spectrum and to test the charge ratio dependence on
the primary composition. The measured charge ratio values were corrected taking
into account the charge-misidentification errors. Data have also been grouped
in five bins of the "vertical surface energy". A fit to a simplified model of
muon production in the atmosphere allowed the determination of the pion and
kaon charge ratios weighted by the cosmic ray energy spectrum.Comment: 14 pages, 10 figure
PENGUIn multi‐instrument observations of dayside high‐latitude injections during the 23 March 2007 substorm
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94875/1/jgra19563.pd
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