This paper proposes a novel engineering approach to control molten metals at high temperatures considering the industrial environment of such materials. To reduce analysis time and cost, in-line ...analysis techniques are more advantageous as they provide real-time information about melt composition. For this reason, recent research works focus on the development of new devices based on LIBS (Laser Induced Breakdown Spectroscopy). These devices allowed for analyzing impurities inside molten metals with great performance. However, improvements related to the immersion probe conception are still required. Indeed, the previous design used bubbling inside the melt, leading to spatial instabilities of the surface analyzed by LIBS. The solution presented here is mechanical stirring by innovative rotary blades which will be a part of an immersion LIBS probe. Their rotation will generate a representative, renewed, and stable surface that will be targeted by spectroscopic techniques in general and particularly by LIBS laser for molten metal monitoring at high temperatures. This solution was validated using experimental tests based on particle imaging velocimetry (PIV) in water at room temperature and then applied to silicon melt at high temperatures. To do so, it was necessary to design a system that allows the introduction of the blade in the melt and controls its rotation.
The structural and chemical properties of advanced nano-devices with a three-dimensional (3D) architecture have been studied at the nanometre scale. An original method has been used to characterize ...gate-all-around and tri-gate silicon nanowire transistor by combining electron tomography and atom probe tomography (APT). Results show that electron tomography is a well suited method to determine the morphological structure and the dimension variations of devices provided that the atomic number contrast is sufficient but without an absolute chemical identification. APT can map the 3D chemical distribution of the atoms in devices but suffers from strong distortions in the dimensions of the reconstructed volume. These may be corrected using a simple method based on atomic density correction and electron tomography data. Moreover, this combination is particularly useful in helping to understand the evaporation mechanisms and improve APT reconstructions. This paper demonstrated that a full 3D characterization of nano-devices requires the combination of both tomography techniques.
•Combination of electron tomography and atom probe tomography (APT) on gate-all-around and tri-gate transistor.•Simulation of the tip shape during APT analysis to understand the evaporation mechanisms.•Improvement of the APT reconstructions.•Quantitative measurements of concentration in the gate stack of transistor.
The presence of gold on the sidewall of a tapered, single silicon nanowire is directly quantified from core-level nanospectra using energy-filtered photoelectron emission microscopy. The uniform ...island-type partial coverage of gold determined as 0.42 ± 0.06 (∼1.8 ML) is in quantitative agreement with the diameter reduction of the gold catalyst observed by scanning electron microscopy and is confirmed by a splitting of the photothresholds collected from the sidewall, from which characteristic local work functions are extracted using a model of the full secondary electron distributions.
•SAM performances and limitations are illustrated on real practical cases such as the analysis of nanowires and nanodots.•High spatial elemental resolution is shown with the analysis of reference ...semiconducting Al0.7Ga0.3As/GaAs multilayers.•High in-depth elemental resolution is also illustrated. Auger depth profiling with low energy ion beams allows revealing ultra-thin layers (∼1nm).•Analysis of cross-sectional samples is another effective approach to obtain in-depth elemental information.
Scanning Auger microscopy is currently gaining interest for investigating nanostructures or thin multilayers stacks developed for nanotechnologies. New generation Auger nanoprobes combine high lateral (∼10nm), energy (0.1%) and depth (∼2nm) resolutions thus offering the possibility to analyze the elemental composition as well as the chemical state, at the nanometre scale. We report here on the performances and limitations on practical examples from nanotechnology research. The spatial elemental sensitivity is illustrated with the analysis of Al0.7Ga0.3As/GaAs heterostructures, Si nanowires and SiC nanodots. Regarding the elemental in-depth composition, two effective approaches are presented: low energy depth profiling to reveal ultra-thin layers (∼1nm) and analysis of cross-sectional samples.
In this work, we report on the PAS characterization of sintered HfO2 bulk ceramic and HfO2 layers deposited with various methods on a silicon substrate with a layer thickness ranging from 25 to 100 ...nm. PAS measurements are sensitive to the deposition process type and the post-deposition annealing. Chemical and structural characterisations have been performed on the same samples. The PAS results are discussed regarding to the material defects of the different layers. In addition, a built-in electrical field induced by charged defects located at the HfO2/Si interface as well as in the HfO2 layer must be taken into account in the PAS data fitting. Both non-contact internal electrical field measurements and internal electrical field simulations support the PAS finding.
Cystinosis is a rare autosomal recessive disorder characterized by an accumulation of intralysosomal cystine due to a defect in cystine transport across the lysosomal membrane. This disorder can be ...treated specifically using high doses of cysteamine. Accurate measurement of intracellular cystine content is necessary for the diagnosis and monitoring of treatment with cysteamine. Here we describe a new method to measure intracellular cystine. It relies on a liquid chromatography-tandem mass spectrometry assay. We compare this novel method with the cystine-binding protein assay.
Cells were isolated and lysed in the presence of
N-ethylmaleimide to avoid interference from cysteine. After deproteinization, addition of stable isotope d
6 cystine and butylation, cystine was measured using an API 3000 MSMS.
The cystine assay was linear to at least 50 μmol/L. Within-run and between-run coefficients of variation were 2.9% and 5.7% respectively.
It is possible to measure very low concentrations of intracellular cystine with liquid chromatography-tandem mass spectrometry. The results obtained with this novel method correlate very well with those obtained using the cystine-binding protein assay.
A full automated NIR polariscope has been specially built for residual stress measurement in crystal silicon wafers for solar applications. The multiple configurations of the instrument allow ...measuring both the isoclinic and the isochromatic parameters on a full field. A new algorithm has also been developed to extract the maximal shear stress inside the silicon wafers without linking the isoclinic parameter to the isochromatic parameter. Hence, it is straightforward to use and the extraction errors are reduced. Coupling this improved data analysis with the comprehensive capabilities of the test rig, allowed to show that the effect of the cutting process on the residual stress inside the silicon wafers is predominant compared with the effect of the cast process, related to the thermal gradient and impurities.
▶ A thin Si interlayer prevents the oxidation of the substrate in Ge based metal-gate/high-k stacks. ▶ Hard X-ray photoelectron spectroscopy enables a non-destructive analysis of interfaces buried ...several nanometers. ▶ A Hf silicate is formed at the interface between HfO2 and SiO2.
In this contribution, we present results of a non-destructive in-depth analysis of concentration of chemical components at buried interfaces on Ge-based CMOS by means of hard X-ray photoelectron spectroscopy (HAXPES) and low angle X-ray reflectivity (XRR). Two samples composed of a Ge/Si/SiO2/HfO2/TiN stack, with layer and interlayer thicknesses of 2500, 0.9, 0.5, 4.9, 3.4nm and 2500, 0.7, 1, 5.8, 3nm have been studied. The use of electrons with kinetic energies from few eV up to 15keV enables to tune the information depth being able to analyze the desired interface in a non-destructive way. XRR enables the determination of the exact layer thickness and density. The results suggest that the Si interlayer prevents the Ge oxidation. Depth profiles of the electronic structure have been obtained for both samples by following the evolution of the photoemission signal from the Hf 2p3/2 core level as a function of the photoelectron kinetic energy. The depth profile of the electronic structure reveals the presence of a chemical shift of the Hf 2p3/2 core level, which is related to an interfacial bonding state. Our results demonstrate the excellent capability of HAXPES to study buried interfaces in a non-destructive way.
Seismic hazard is associated with recent and present fault activity in mountain ranges. In the Betic-Rif alpine mountain chain, tectonic activity started in the Cretaceous, and topographic uplift ...continues since Tortonian times as a consequence of the NW–SE oblique convergence between Africa and Eurasia. The deformation is active and produces seismicity that sometimes has catastrophic consequences. The Al Hoceima earthquake (February 24, 2004), considered one of the largest earthquakes ever recorded instrumentally in the westernmost Mediterranean (
M
=
6.3), caused great damage in the region. Seismological studies agree that the main shock was situated on land, at the limit between the External and Internal Zones of the Rif, at a depth of 10–14 km. The focal mechanism points to a strike-slip solution with a NW–SE oriented
P axis, quite similar to those of the significant 1994 earthquake swarm located to the north. The epicenter aftershocks distribution would signal the presence of a N–S oriented sinistral fault, activated by the NW–SE regional compression associated to plate boundary convergence. In this setting, the seismogenic fault ruptures related to these seismic events are expected to have reached the Earth's surface. However, detailed field work carried out 1 month after the earthquake does not evidence any N–S strike-slip coseismic fault in the epicentral area. The main observed effects were landslides, damages to constructions, and locally open cracks indicating an unexpected NW–SE extension. Scarce N–S faults are normal, the main ones being located several kilometers away from the epicentral area. To explain this apparent contradiction between geological and seismological observations, we propose a decoupled tectonic model with crustal detachments that separate a deep brittle crust from an upper crust undergoing uplift, and the development of large folds and normal faults. This geological setting, common to internal zones of cordilleras, may need to be taken into account in future paleoseismicity studies and in the assessment of seismic hazard.
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