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18188
21/09/2018

Nanosecond laser defects induced in crystalline silicon annealed: identification, localization and electrical impact

R.MONFLIER, H.RIZK, T.TABATA, J.ROUL, E.IMBERNON, S.BONINELLI, M.ITALIA, A.LA MAGNA, F.MAZZAMUTO, P.ACOSTA ALBA, S.KERDILES, F.CRISTIANO

MPN, SCREEN-LASSE, I2C, TEAM, CNR-IMM, Catania, CEA-LETI

Manifestation avec acte : International Conference on Ion Implantation Technology ( IIT ) 2018 du 16 septembre au 21 septembre 2018, Wurzburg (Allemagne), Septembre 2018, 1p. , N° 18188

Lien : https://hal.laas.fr/hal-01803955

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Laser Thermal Annealing (LTA) in conjunction with ion implantation has been demonstrated to be a very effective method to achieve heavily doped and localized regions needed in both advanced MOSFET and solar cells technology. In some cases, degradation of the electrical properties of the laser doped regions has been reported, including increased leakage current in p-n junctions, reduced carrier mobility and breakdown voltage shift in MOS transistors or reduced carrier lifetime in solar cells, which are attributed to laser-induced damage, including impurity penetration during anneal or point defect generation during melt recrystallization. In this work, we present a comprehensive investigation of laser induced damage by implementing a methodology allowing the identification and the localization of the defects as well as the investigation of their impact on the properties of the annealed regions.

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18210
01/08/2018

Liquid-Crystal alignment by a nanoimprinted grating for wafer-scale fabrication of tunable devices

B.SADANI, B.BOISNARD, X.LAFOSSE, T.CAMPS, J.B.DOUCET, E.DARAN, C.PARANTHOEN, C.LEVALLOIS, L.DUPONT, S.BOUCHOULE, V.BARDINAL

MICA, LPN, TEAM, INSA Rennes, C2N

Revue Scientifique : IEEE Photonics Technology Letters, Vol.30, N°15, pp.1388-1391, Août 2018 , N° 18210

Lien : https://hal.laas.fr/hal-01839878

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A simple technology is demonstrated for wafer-scale fabrication of liquid-crystal (LC) microcells that can be integrated in active optoelectronic devices. Fabrication of 1.55µm tunable Fabry-Perot optical micro-filter arrays is achieved owing to the insertion of a single nanoimprinted polymer grating dedicated to LC alignment and to the soft thermal transfer of a dry thick resist film between two highly reflective mirrors. The filter exhibits a spectral tuning range of 102nm with only 18V applied, as well as negligible internal loss, which makes it suitable for being inserted in a laser cavity. This constitutes a key step toward large-scale integration of widely-tunable photonic devices such as VCSELs using LC technology.

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18177
01/08/2018

Direct patterning of polymer optical periodic nanostructures on CYTOP for visible light waveguiding

M.DIEZ GARCIA, V.RAIMBAULT, S.JOLY, L.OYHENART, J.B.DOUCET, I.OBIETA, C.DEJOUS, L.BECHOU

IMS Bordeaux, MICA, TEAM, Tecnalia Research & Innovation

Revue Scientifique : Optical Materials, Vol.82, pp.21-29, Août 2018 , N° 18177

Lien : https://hal.archives-ouvertes.fr/hal-01825019

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Optical waveguides and grating couplers based on polymer nanostructures are now considered as promising technologies for integrated biophotonic sensing systems. Commonly, structuration and patterning of polymers at the submicron scale requires the use of time and cost-consuming equipments such as electron beam lithography. Direct patterning of high refractive index polymer devices on CYTOP is now achievable and provides symmetric waveguides with top water-like claddings. In addition, transparency of polymers makes them suitable for operation in the visible range, being of major interest for biophotonic applications. In this paper, we report on the fabrication process of polymer submicronic single-mode waveguides on CYTOP for visible light operation. Subwavelength grating couplers with a pitch lower than 300 nm were fabricated to couple the input light into a 350 nm square cross-section waveguide. The whole device is imprinted in a single step using soft stamp lithography with a minimal residual layer. Finally, optical characterizations demonstrate a state-of-the-art transmission efficiency (around 1.5%) at the selected operating wavelength of 507 nm for different coupling angles in good agreement with simulations.

143933
18167
26/06/2018

Micromachining-Compatible, Facile Fabrication of Polymer Nanocomposite Spin Crossover Actuators

M.DMANRIQUE JUAREZ, F.MATHIEU, A.LABORDE, S.RAT, V.SHALABAEVA, P.DEMONT, O.THOMAS, L.SALMON, T.LEICHLE, L.NICU, G.MOLNAR, A.BOUSSEKSOU

MEMS, I2C, TEAM, LCC, CIRIMAT, LSIS, ENSAM, Lille

Revue Scientifique : Advanced Functional Materials, Juin 2018, DOI 10.1002/adfm.201801970 , N° 18167

Lien : https://hal.laas.fr/hal-01816709

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[Fe II (Htrz) 2 (trz)](BF 4) spin crossover particles of 85 nm mean size were dispersed in an SU-8 polymer matrix and spray-coated onto silicon microcantilevers. The subsequent photo-thermal treatment of the polymer resist led to micrometer thick, smooth and homogeneous coatings, which exhibited well-reproducible actuation upon the thermally-induced spin transition. The actuation amplitude as a function of temperature was accurately determined by combining an integrated piezoresisitive detection with external optical interferometry, which allowed for the assessment of the associated actuation force (9.4 mN), stress (28 MPa), strain (1.0 %) and work density (140 mJ/cm 3) through a stratified beam model. The dynamical mechanical characterization of the films evidenced an increase of the resonance frequency and a concomitant decrease of the damping in the high temperature phase, which arise due to a combined effect of the thickness and mechanical property changes. The spray-coating approach was also successfully extended to scale up the actuators for the cm-range on a polymer substrate providing perspectives for biomimetic soft actuators.

143894
18168
05/06/2018

Self-Aligned Functionalization Approach to Order Neuronal Networks at the Single-Cell Level

A.CASANOVA, MC.BLATCHE, C.FERRE, H.MARTIN, D.GONZALES DUNIA, L.NICU, G.LARRIEU

MPN, I2C, INSERM, MEMS

Revue Scientifique : Langmuir, Vol.34, N°22, pp.6612-6620, Juin 2018 , N° 18168

Lien : https://hal.laas.fr/hal-01816434

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Despite significant progress, our knowledge of the functioning of the central nervous system still remains scarce to date. A better understanding of its behavior, in either normal or diseased conditions, goes through an increased knowledge of basic mechanisms involved in neuronal function, including at the single-cell level. This has motivated significant efforts for the development of miniaturized sensing devices to monitor neuronal activity with high spatial and signal resolution. One of the main challenges remaining to be addressed in this domain is, however, the ability to create in vitro spatially ordered neuronal networks at low density with a precise control of the cell location to ensure proper monitoring of the activity of a defined set of neurons. Here, we present a novel self-aligned chemical functionalization method, based on a repellant surface with patterned attractive areas, which permits the elaboration of low-density neuronal network down to individual cells with a high control of the soma location and axonal growth. This approach is compatible with complementary metal-oxide–semiconductor line technology at a wafer scale and allows performing the cell culture on packaged chip outside microelectronics facilities. Rat cortical neurons were cultured on such patterned surfaces for over one month and displayed a very high degree of organization in large networks. Indeed, more than 90% of the network nodes were settled by a soma and 100% of the connecting lines were occupied by a neurite, with a very good selectivity (low parasitic cell connections). After optimization, networks composed of 75% of unicellular nodes were obtained, together with a control at the micron scale of the location of the somas. Finally, we demonstrated that the dendritic neuronal growth was guided by the surface functionalization, even when micrometer scale topologies were encountered and we succeeded to control the extension growth along one-dimensional-aligned nanostructures with sub-micrometrical scale precision. This novel approach now opens the way for precise monitoring of neuronal network activity at the single-cell level.

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18117
01/06/2018

A review on mechanical considerations for chronically-implanted neural probes

C.BERGAUD, A.LECOMTE, E.DESCAMPS

MEMS, MICA

Revue Scientifique : Journal of Neural Engineering, Vol.15, N°3, Juin 2018 , N° 18117

Lien : https://hal.laas.fr/hal-01764292

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This review intends to present a comprehensive analysis of the mechanical considerations for chronically-implanted neural probes. Failure of neural electrical recordings or stimulation over time has shown to arise from foreign body reaction and device material stability. It seems that devices that match most closely with the mechanical properties of the brain would be more likely to reduce the mechanical stress at the probe/tissue interface, thus improving body acceptance. The use of low Young's modulus polymers instead of hard substrates is one way to enhance this mechanical mimetism, though compliance can be achieved through a variety of means. The reduction of probe width and thickness in comparison to a designated length, the use of soft hydrogel coatings and the release in device tethering to the skull, can also improve device compliance. Paradoxically, the more compliant the device, the more likely it will fail during the insertion process in the brain. Strategies have multiplied this past decade to offer partial or temporary stiffness to the device to overcome this buckling effect. A detailed description of the probe insertion mechanisms is provided to analyze potential sources of implantation failure and the need for a mechanically-enhancing structure. This leads us to present an overview of the strategies that have been put in place over the last ten years to overcome buckling issues. Particularly, great emphasis is put on bioresorbable polymers and their assessment for neural applications. Finally, a discussion is provided on some of the key features for the design of mechanically-reliable, polymer-based next generation of chronic neuroprosthetic devices.

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18129
28/05/2018

Nanoscale measurements of phosphorous-induced lattice expansion in nanosecond laser annealed germanium

S.BONINELLI, R.MILAZZO, R.CARLES, F.HOUDELLIER, R.DUFFY, K.HUET, A.LA MAGNA, E.NAPOLITANI, F.CRISTIANO

CNR-IMM, Catania, University of Padova, CEMES/CNRS, Tyndall, SCREEN-LASSE, MPN

Revue Scientifique : APL Materials, Vol.6, N°5, 058504p., Mai 2018 , N° 18129

Lien : https://hal.archives-ouvertes.fr/hal-01796115

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Abstract

Laser Thermal Annealing (LTA) at various energy densities was used to recrystallize and activate amorphized germanium doped with phosphorous by ion implantation. The structural modifications induced during the recrystallization and the related dopant diffusion were first investigated. After LTA at low energy densities, the P electrical activation was poor while the dopant distribution was mainly localized in the poly- crystalline Ge resulting from the anneal. Conversely, full dopant activation (up to 1 × 10 20 cm 3 ) in a perfectly recrystallized material was observed after annealing at higher energy densities. Measurements of lattice parameters performed on the fully activated structures show that P doping results in a lattice expansion, with a perpen- dicular lattice strain per atom β Ps = +0.7 ± 0.1 Å 3 . This clearly indicates that, despite the small atomic radius of P compared to Ge, the “electronic contribution” to the lattice parameter modification (due to the increased hydrostatic deformation potential in the conduction band of P doped Ge) is larger than the “size mismatch contribu- tion” associated with the atomic radii. Such behavior, predicted by theory, is observed experimentally for the first time, thanks to the high sensitivity of the measurement techniques used in this work

143594
18179
23/05/2018

Simple Synthetic Molecular Hydrogels from Self- Assembling Alkylgalactonamides as Scaffold for 3D Neuronal Cell Growth

A.CHALARD, L.VAYSSE, P.JOSEPH, L.MALAQUIN, S.ASSIE-SOULEILLE, B.LONETTI, J.C.SOL, I.LOUBINOUX, J.FITREMANN

MILE, INSERM, ELIA, I2C, IMRCP

Revue Scientifique : ACS applied materials & interfaces, Vol.10, N°20, pp.17004-17017, Mai 2018 , N° 18179

Lien : https://hal.laas.fr/hal-01810656

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Abstract

In this work, we demonstrated that the hydrogel obtained from a very simple and single synthetic molecule, N-heptyl-galactonamide was a suitable scaffold for the growth of neuronal cells in 3D. We evidenced by confocal microscopy the presence of the cells into the gel up to a depth of around 200 µm, demonstrating that the latter was permissive to cell growth and enabled a true 3D colonization and organization. It also supported successfully the differentiation of adult human neuronal stem cells (hNSCs) into both glial and neuronal cells and the development of a really dense neurofilament network. So the gel appears to be a good candidate for neural tissue regeneration. In contrast with other molecular gels described for cell culture, the molecule can be obtained at the gram scale by a one-step reaction. The resulting gel is very soft, a quality in accordance with the aim of growing neuronal cells, that requires low modulus substrates similar to the brain. But because of its fragility, specific procedures had to be implemented for its preparation and for cell labeling and confocal microscopy observations. Notably, the implementation of a controlled slow cooling of the gel solution was needed to get a very soft but nevertheless cohesive gel. In these conditions, very wide straight and long micrometric fibers were formed, held together by a second network of flexible narrower nanometric fibers. The two kinds of fibers guided the neurite and glial cell growth in a different way. We also underlined the importance of a tiny difference in the molecular structure on the gel performances: parent molecules, differing by a one-carbon increment in the alkyl chain length, N-hexyl-galactonamide and N-octyl-galactonamide, were not as good as N-heptyl-galactonamide. Their differences were analysed in terms of gel fibers morphology, mechanical properties, solubility, chain parity and cell growth.

143937
18160
23/05/2018

Conception et réalisation de microdispositifs électrochimiques, pour l’analyse de l’activité bioénergétique de mitochondries isolées, dans le cadre de la mise au point de traitements innovants des leucémies aiguës myéloïdes

G.LEMERCIER

MICA

Doctorat : Université de Toulouse III - Paul Sabatier, Mai 2018, 179p., Président: L.CASTEILLA, Rapporteurs: P.MAILLEY, R.ROSSIGNOL, Examinateurs: R.FERRIGNO, S.ARBAULT, P.TEMPLE-BOYER, Directeurs de thèse: J.E.SARRY, J.LAUNAY , N° 18160

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The role of mitochondria have been restricted to oxidative phosphorylation for a long time. Now it is clear that they are also the main sources of reactive oxygen species, implied in oxidative stress and cell-to-cell signaling. Thus, mitochondrial malfunction is potentially the cause of the appearance and the progression of diseases linked to ageing like cancers and neurodegenerative troubles. In the frame of acute myeloid leukemia, studies governed by Jean-Emmanuel Sarry of the Cancer Research Center of Toulouse, showed that it is possible to improve the efficacy of current chemotherapies by targeting mitochondria’s function. In this context, the objective of the thesis presented here consist in the design and the manufacturing of electrochemical micro-sensors, dedicated to the analysis of the metabolic activity of isolated mitochondria. The manufacturing occurred in the clean room facilities of the Laboratory for Analysis and Architecture of Systems of Toulouse under the supervision of Jérôme Launay and Pierre Temple-Boyer, researchers specialized in the development of solutions aiming the detection of species diluted in solution. Finally, a complete system ensuring the coupling with microscopy and fluidics have been realized, validated, and patented. The results obtained allow us to consider the analysis at the scale of the single mitochondrion with a parallelized approach, thing that have never been made.

Résumé

La mitochondrie est restée longtemps cantonnée au rôle de centrale énergétique cellulaire. On sait désormais qu’elle est aussi la principale source d’espèces réactives oxygénées, impliquées dans le stress oxydant et la signalisation inter-cellulaire. Le dérèglement de l’activité mitochondriale est ainsi susceptible d’être la cause de l’apparition et de la progression de maladies associées au vieillissement, comme le cancer et les maladies neurodégénératives. Dans le cadre de la leucémie aiguë myéloïde, des études menées par l’équipe dirigée par Jean-Emmanuel Sarry du Centre de Recherche en Cancérologie de Toulouse, ont montré qu’il est possible de sensibiliser les cellules jusqu’alors résistantes à la chimiothérapie, en ciblant préalablement la fonction mitochondriale. C’est dans ce contexte que s’inscrit le sujet de cette de thèse, portant sur la conception et la réalisation de micro-capteurs électrochimiques dédiées à l’analyse du métabolisme mitochondrial, à l’échelle de la mitochondrie isolée. La fabrication des microsystèmes s’est déroulée dans la salle blanche du Laboratoire d’Analyse et d’Architecture des Systèmes de Toulouse, sous l’encadrement des chercheurs Jérôme Launay et Pierre Temple-Boyer, spécialisés dans la conception de capteurs pour la détection d’espèces en phase liquide. Finalement, un système complet assurant le couplage à la microscopie et à la gestion des fluides a été fabriqué, validé, et breveté. Les résultats obtenus nous permettent d’envisager l’analyse à l’échelle de la mitochondrie unique par une approche parallélisée, ce qui n’a encore jamais été réalisé.

143853
18066
01/04/2018

Computational fluid dynamics simulation of the ALD of alumina from TMA and H2O in a commercial reactor

G.P.GAKIS, H.VERGNES, E.SCHEID, C.VAHLAS, B.CAUSSAT, A.BOUDOUVIS

LGC, MPN, CIRIMAT, NTUA

Revue Scientifique : Chemical Engineering Research and Design: Transactions of the Institution of Chemical Engineers Part A, Vol.132, pp.795-811, Avril 2018 , N° 18066

Lien : https://hal.archives-ouvertes.fr/hal-01730196

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A three-dimensional Computational Fluid Dynamics model is built for a commercial Atomic Layer Deposition (ALD) reactor, designed to treat large area 20 cm substrates. The model aims to investigate the effect of the reactor geometry and process parameters on the gas flow and temperature fields, and on the species distribution on the heated substrate surface, for the deposition of Al2O3 films from trimethyl aluminum and H2O. The investigation is performed in transient conditions, without considering any surface reaction. A second CFD model is developed for the feeding system of the reactor, in order to calculate the unknown reactant inlet flow rates. The two models are coupled via a computational strategy dictated by the available experimental measurements. Results show that a purging flow entering the reactor through its loading door affects the flow field above the substrate surface and causes non-uniformity in the temperature and reactants concentration on the substrate surface. During the TMA pulse, a recirculation sets in above the substrate surface, leading to a non-uniform distribution of species on the surface.

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