115 research outputs found
Transistors MOS sur films minces de Silicium-sur-Isolant (SOI) complÚtement désertés pour le noeud technologique 10nm
Depuis plusieurs gĂ©nĂ©rations technologiques, la rĂ©duction des dimensions des transistors Ă effet de champ MĂ©tal-Oxyde-Semiconducteur (MOSFET) n'est plus suffisante pour augmenter Ă elle seule les performances des circuits intĂ©grĂ©s. Pour les circuits logiques Ă partir du nĆud 28 nm, l'architecture planaire sur silicium massif a Ă©tĂ© abandonnĂ©e au profit de structures Ă canaux entiĂšrement dĂ©sertĂ©s (Fully Depleted). MalgrĂ© l'avantage apportĂ© par la fabrication de ces transistors (FinFET ou Fully Depleted Silicon On Insulator FDSOI planaire), l'introduction et l'optimisation des contraintes mĂ©caniques dans le canal restent indispensables. Ce travail de recherche prĂ©sente l'intĂ©gration de divers procĂ©dĂ©s de fabrication permettant de contraindre les MOSFET planaires sur SOI. L'efficacitĂ© des couches de nitrure (CESL) contraints, de l'Ă©pitaxie des source/drain en SiGe, des substrats de silicium contraints sur isolant (sSOI) ainsi que l'effet de l'orientation du canal a Ă©tĂ© mesurĂ©e pour des longueurs de grille jusque 14 nm. L'intĂ©gration de MOSFET Ă grille damascĂšne (gate-last) a Ă©galement Ă©tĂ© dĂ©veloppĂ©e sur SOI. En particulier, l'intĂ©rĂȘt de ce type de grille pour ajuster la tension de seuil et pour optimiser les contraintes a Ă©tĂ© Ă©tudiĂ©. Finalement des perspectives sont prĂ©sentĂ©es pour le nĆud 10 nm. Des simulations mĂ©caniques ont permis de valider une structure innovante permettant un transfert de contraintes depuis une couche de SiGe enterrĂ©e vers le canal. Par ailleurs, une intĂ©gration basĂ©e sur un procĂ©dĂ© d'espaceurs sacrificiels (SIT) est prĂ©sentĂ©e. Celle-ci permet de fabriquer des transistors Ă forte densitĂ© sur SOI.Since several technological nodes, the scaling of Metal-Oxide-Semiconductor field effect transistors (MOSFET) alone is not sufficient to increase performances of integrated circuits. For numerical circuits beyond the 28 nm node, the planar architecture on bulk silicon has been discarded in favor of structures with fully depleted channels. Despite the advantage of such transistors (FinFET or planar Fully Depleted Silicon On Insulator FDSOI), the use and the optimization of mechanical stress in the channel remains mandatory. This study presents the integration of various fabrication processes allowing to stress planar MOSFET on SOI. The efficiency of stressed nitride layers (CESL), of SiGe epitaxially raised source/drain (RSD) regions, of strained silicon on insulator (sSOI) substrates as well as the effect of the channel orientation has been measured for gate lengths down to 14 nm. The integration of replacement metal gate (gate-last) has been developed on SOI. Particularly, the interest of this kind of gate for threshold voltage adjustment and for stress optimization has been studied. Finally, perspectives for the 10 nm node are presented. Mechanical simulations enabled to validate an innovative structure which transfers stress from a buried SiGe layer to the channel. Moreover, an integration based on sacrificial spacers (SIT) is presented. It enables to fabricate high density transistors on SOI.SAVOIE-SCD - Bib.Ă©lectronique (730659901) / SudocGRENOBLE1/INP-Bib.Ă©lectronique (384210012) / SudocGRENOBLE2/3-Bib.Ă©lectronique (384219901) / SudocSudocFranceF
Lâagriculture biologique contribue-t-elle au bien-eÌtre ?
Full Text / Article completThrough a case study of a producer association of organic fruit and vegetables in the Loire Valley Region of France (Loire Ocean Bio), this article proposes several approaches for understanding the potential links between organic farming and health and well-being. In the cases encountered by the authors, the classic utilitarian approach used by economists regarding health and well-being does not prove very useful in analyzing these links. Multidimensional measurements of the determinants of health and well-being, such as those proposed by Stiglitz report (Stiglitz, Sen and Fitoussi, 2009), prove to be better suited in this matter. Using their framework, this article highlights the finding that there appears to be a mutually reinforcing relationship between organic agriculture and health and well-being. That is to say, on certain points, organic agriculture helps to improve the quality of life in the region concerned, while at the same time the interests of health and well-being are of a central concern to organic producers.A travers lâeÌtude de cas dâune association de producteurs de fruits et leÌgumes biologiques en Pays de la Loire (Bio Loire OceÌan), cet article propose quelques pistes pour appreÌhender les liens potentiels entre agriculture biologique et bien-eÌtre. Dans les cas rencontreÌs par les auteurs, lâapproche utilitariste des eÌconomistes du bien-eÌtre se reÌveÌle peu utile pour analyser ces liens. Les mesures multidimensionnelles des deÌterminants du bien-eÌtre, telles que celle proposeÌe par le rapport Stiglitz (Stiglitz, Sen et Fitoussi, 2009), sâ aveÌrent plus opeÌrationnelles en la matieÌre. Sâappuyant sur cette grille de lecture, lâarticle met en eÌvidence le fait que ce lien est dual. Sâil est possible de dire que, sur certains points, lâagriculture bio favorise la production de capabiliteÌs et la qualiteÌ de vie sur le territoire consideÌreÌ, il apparaiÌt eÌgalement que la recherche de bien-eÌtre est au cĆur du projet politique des producteurs rencontreÌs
Cometary water expansion velocity from OH line shapes
We retrieve the H_2O expansion velocity in a number of comets, using the
18-cm line shapes of the OH radical observed with the Nan\c{c}ay radio
telescope. The H_2O velocity is derived from the large base of a trapezium
fitted to the observed spectra. This method, which was previously applied to 9
comets, is now extended to 30 further comets. This allows us to study the
evolution of their water molecule outflow velocity over a large range of
heliocentric distances and gas production rates. Our analysis confirms and
extends previous analyses. The retrieved expansion velocities increases with
increasing gas production rates and decreasing heliocentric distances.
Heuristic laws are proposed, which could be used for the interpretation of
observations of cometary molecules and as a touchstone for hydrodynamical
models. The expansion velocities retrieved from 18 cm line shapes are larger
than those obtained from millimetric observations of parent molecules with
smaller fields of view, which demonstrates the acceleration of the gas with
cometocentric distance. Our results are in reasonable quantitative agreement
with current hydrodynamical models of cometary atmospheres.Comment: Accepted for publication in Astronomy & Astrophysic
TWEAK Appears as a Modulator of Endometrial IL-18 Related Cytotoxic Activity of Uterine Natural Killers
BACKGROUND: TWEAK (Tumor necrosis factor like WEAK inducer of apoptosis) is highly expressed by different immune cells and triggers multiple cellular responses, including control of angiogenesis. Our objective was to investigate its role in the human endometrium during the implantation window, using an ex-vivo endometrial microhistoculture model. Indeed, previous results suggested that basic TWEAK expression influences the IL-18 related uNK recruitment and local cytotoxicity.
METHODOLOGY/PRINCIPAL FINDINGS: Endometrial biopsies were performed 7 to 9 days after the ovulation surge of women in monitored natural cycles. Biopsies were cut in micro-pieces and cultured on collagen sponge with appropriate medium. Morphology, functionality and cell death were analysed at different time of the culture. We used this ex vivo model to study mRNA expressions of NKp46 (a uNK cytotoxic receptor) and TGF-beta1 (protein which regulates uNK cytokine production) after adjunction of excess of recombinant IL-18 and either recombinant TWEAK or its antibody. NKp46 protein expression was also detailed by immunohistochemistry in selected patients with high basic mRNA level of IL-18 and either low or high mRNA level of TWEAK. The NKp46 immunostaining was stronger in patients with an IL-18 over-expression and a low TWEAK expression, when compared with patients with both IL-18 and TWEAK high expressions. We did not observe any difference for TWEAK expression when recombinant protein IL-18 or its antibody was added, or conversely, for IL-18 expression when TWEAK or its antibody was added in the culture medium. In a pro-inflammatory environment (obtained by an excess of IL-18), inhibition of TWEAK was able to increase significantly NKp46 and TGF-beta1 mRNA expressions.
CONCLUSIONS/SIGNIFICANCE: TWEAK doesn't act on IL-18 expression but seems to control IL-18 related cytotoxicity on uNK cells when IL-18 is over-expressed. Thus, TWEAK appears as a crucial physiological modulator to prevent endometrial uNK cytotoxicity in human
Strain transfer structure as a mobility booster for fully-depleted SOI MOSFETs at the 10nm node
International audienc
Observations of the Oh Radio Lines of Comets at Nançay - Recent Developments
International audienc
Observations of the Oh Radio Lines of Comets at Nançay - Recent Developments
International audienc
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