Transistors MOS sur films minces de Silicium-sur-Isolant (SOI) complètement désertés pour le noeud technologique 10nm

Depuis plusieurs générations technologiques, la réduction des dimensions des transistors à effet de champ Métal-Oxyde-Semiconducteur (MOSFET) n'est plus suffisante pour augmenter à elle seule les performances des circuits intégrés. Pour les circuits logiques à partir du nœud 28 nm, l'architecture planaire sur silicium massif a été abandonnée au profit de structures à canaux entièrement désertés (Fully Depleted). Malgré l'avantage apporté par la fabrication de ces transistors (FinFET ou Fully Depleted Silicon On Insulator FDSOI planaire), l'introduction et l'optimisation des contraintes mécaniques dans le canal restent indispensables. Ce travail de recherche présente l'intégration de divers procédés de fabrication permettant de contraindre les MOSFET planaires sur SOI. L'efficacité des couches de nitrure (CESL) contraints, de l'épitaxie des source/drain en SiGe, des substrats de silicium contraints sur isolant (sSOI) ainsi que l'effet de l'orientation du canal a été mesurée pour des longueurs de grille jusque 14 nm. L'intégration de MOSFET à grille damascène (gate-last) a également été développée sur SOI. En particulier, l'intérêt de ce type de grille pour ajuster la tension de seuil et pour optimiser les contraintes a été étudié. Finalement des perspectives sont présentées pour le nœud 10 nm. Des simulations mécaniques ont permis de valider une structure innovante permettant un transfert de contraintes depuis une couche de SiGe enterrée vers le canal. Par ailleurs, une intégration basée sur un procédé d'espaceurs sacrificiels (SIT) est présentée. Celle-ci permet de fabriquer des transistors à forte densité 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.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

L’agriculture biologique contribue-t-elle au bien-être ?

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 l’étude de cas d’une association de producteurs de fruits et légumes biologiques en Pays de la Loire (Bio Loire Océan), cet article propose quelques pistes pour appréhender les liens potentiels entre agriculture biologique et bien-être. Dans les cas rencontrés par les auteurs, l’approche utilitariste des économistes du bien-être se révèle peu utile pour analyser ces liens. Les mesures multidimensionnelles des déterminants du bien-être, telles que celle proposée par le rapport Stiglitz (Stiglitz, Sen et Fitoussi, 2009), s’ avèrent plus opérationnelles en la matière. S’appuyant sur cette grille de lecture, l’article met en évidence le fait que ce lien est dual. S’il est possible de dire que, sur certains points, l’agriculture bio favorise la production de capabilités et la qualité de vie sur le territoire considéré, il apparaît également que la recherche de bien-être est au cœur du projet politique des producteurs rencontrés

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

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Observations of the Oh Radio Lines of Comets at Nançay - Recent Developments

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Maser emissions from comets

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Maser emissions from comets

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Maser emissions from comets

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Observations of the Oh Radio Lines of Comets at Nançay - Recent Developments

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