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Dhalluin F.,CNRS Laboratory for Microelectronics Technolgy | Baron T.,CNRS Laboratory for Microelectronics Technolgy | Ferret P.,CEA Grenoble | Salem B.,CNRS Laboratory for Microelectronics Technolgy | And 2 more authors.
Applied Physics Letters | Year: 2010

We grew Si nanowires by chemical vapor deposition, via the vapor liquid solid growth, using silane as gaseous precursor and gold as catalyst. The results show that the nanowire length depends on their diameter. For nanowires with diameter under 100 nm, the length increases when diameter increases, because of an increase in the growth velocity. For the thicker diameter (d>100 nm), length decreases when diameter increases, due to an apparent incubation time which is all the higher as the diameter is high. We propose a semiempirical model combining Gibbs-Thomson effect and incubation time, which shows good agreement with the experimental data. © 2010 American Institute of Physics.

Rosaz G.,CNRS Laboratory for Microelectronics Technolgy | Rosaz G.,CEA Grenoble | Salem B.,CNRS Laboratory for Microelectronics Technolgy | Pauc N.,CEA Grenoble | And 3 more authors.
Applied Physics Letters | Year: 2011

We demonstrate in this paper the possibility to vertically integrate SiGe nanowires in order to use them as vertical channel for field-effect transistors (FETs). We report a threshold voltage close to 3.9 V, an ION/I OFF ratio of 104. The subthreshold slope was estimated to be around 0.9 V/decade and explained by a high traps density at the nanowire core/oxide shell interface with an estimated density of interface traps D it ∼ 1.2 × 1013cm-2eV-1. Comparisons are made with both vertical Si and horizontal SiGe FETs performances. © 2011 American Institute of Physics.

Bertaud T.,CNRS Institute for Microelectronics, Electromagnetism, and Photonics: Hyperfrequency and Characterization lab | Bertaud T.,CNRS Laboratory for Microelectronics Technolgy | Blonkowski S.,STMicroelectronics | Bermond C.,CNRS Institute for Microelectronics, Electromagnetism, and Photonics: Hyperfrequency and Characterization lab | And 4 more authors.
IEEE Electron Device Letters | Year: 2010

This letter deals with the electrical and wideband frequency characterizations of metalinsulatormetal capacitors integrating medium-κ material, ZrO2. In particular, this letter focuses on the frequency effect on the voltage linearity of these capacitors and material. The dependence of the voltagecapacitance coefficient (VCC) α is, for the first time, studied from 1 kHz to 1 GHz. Intrinsic or extrinsic material origin of the VCC are discussed. © 2006 IEEE.

Verreycken T.,TU Eindhoven | Sadeghi N.,CNRS Laboratory for Microelectronics Technolgy | Bruggeman P.J.,TU Eindhoven | Bruggeman P.J.,University of Minnesota
Plasma Sources Science and Technology | Year: 2014

The time-resolved OH density in a nanosecond pulsed filamentary discharge in an atmospheric pressure He-H2O(0.05%) mixture is measured using laser induced fluorescence. The lifetime of the excited OH(A) state is found to be strongly time dependent during the plasma pulse, with the shortest decay time occurring at the moment the plasma is switched off. The measured LIF intensity is corrected for this time-resolved quenching and calibrated using Rayleigh scattering. Time-resolved electron density , He (3S1) metastable density , gas temperature and optical emission are presented and used in the interpretation of the observed time dependence of the OH density. Based on these experimental data, it is shown that for the present discharge conditions, OH is mainly produced by charge transfer reactions to water followed by dissociative recombination of the water ion. In addition, two often encountered issues with the calibration of OH LIF are highlighted with an example. © 2014 IOP Publishing Ltd.

Demichel O.,CNRS Physics of Materials and Microstructures | Calvo V.,CNRS Physics of Materials and Microstructures | Besson A.,CNRS Physics of Materials and Microstructures | Noe P.,CNRS Physics of Materials and Microstructures | And 5 more authors.
Nano Letters | Year: 2010

The past decade has seen the explosion of experimental results on nanowires grown by catalyzed mechanisms. However, few are known on their electronic properties especially the influence of surfaces and catalysts. We demonstrate by an optical method how a curious electron-hole thermodynamic phase can help to characterize volume and surface recombination rates of silicon nanowires (SiNWs). By studying the electron-hole liquid dynamics as a function of the spatial confinement, we directly measured these two key parameters. We measured a surface recombination velocity of passivated SiNWs of 20 cm s-1, 100 times lower than previous values reported. Furthermore, the volume recombination rate of gold-catalyzed SiNWs is found to be similar to that of a high-quality three-dimensional silicon crystal; the influence of the catalyst is negligible. These results advance the knowledge of SiNW surface passivation and provide essential guidance to the development of efficient nanowire-based devices. © 2010 American Chemical Society.

Tomba C.,CNRS Neel Institute | Tomba C.,CNRS Laboratory for Microelectronics Technolgy | Braini C.,CNRS Neel Institute | Wu B.,CNRS Neel Institute | And 2 more authors.
Soft Matter | Year: 2014

Neurons acquire their functional and morphological axo-dendritic polarity by extending, from competing minor processes (neurites), one long axon among numerous dendrites. We employed complementary sets of micropatterns built from 2 and 6 μm wide stripes of various lengths to constrain hippocampal neuron shapes. Using these geometries, we have (i) limited the number of neuronal extensions to obtain a minimal in vitro system of bipolar neurons and (ii) controlled the neurite width during growth by the generation of a progressive cell shape asymmetry on either side of the cellular body. From this geometrical approach, we gained a high level of control of each neurite length and of the localization of axonal specification. To analyze these results, we developed a model based on a width and polarization dependent neurite elongation rate and on the existence of a critical neurite length that sets the axonal fate. Our data on the four series of micro-patterns developed for this study are described by a single set of growth parameters, well supported by experiments. The control of neuronal shapes by adhesive micro-patterns thereby offers a novel paradigm to follow the dynamical process of neurite lengthening and competition through the process of axonal polarization. This journal is © the Partner Organisations 2014.

Beaudoin A.,Université de Sherbrooke | Salem B.,CNRS Laboratory for Microelectronics Technolgy | Baron T.,CNRS Laboratory for Microelectronics Technolgy | Gentile P.,Joseph Fourier University | Morris D.,Université de Sherbrooke
Physical Review B - Condensed Matter and Materials Physics | Year: 2014

The n-doped and undoped silicon nanowires grown by chemical vapor deposition on quartz substrate were characterized using optical-pump terahertz-probe transmission experiments. Temporal decays of the differential transmission measurements are reproduced using a biexponential function with an initial photocarrier lifetime of ∼2 ps and a longer decay time of 10 ps to a few tens of picoseconds. Based on the influence of the laser fluence, a carrier capture and recombination scenario is proposed to explain these temporal decay curves. For both samples, the capture of photocarriers by the traps present on the surface of the nanowires plays an important role in the observed photoconductivity dynamics. Frequency-dependent complex photoconductivity data curves are extracted from the terahertz (THz) traces taken at different optical-pump THz-probe delays. These data curves are reproduced using a plasmon resonance model. The fitting procedure allows us to determine carrier scattering times of about 28±6 and 14±4 fs for the undoped and doped samples, respectively. Our results show that defects and ionized impurities introduced by n doping the silicon nanowires reduce the photocarrier mobility and lifetime. © 2014 American Physical Society.

Robert P.,Aix - Marseille University | Nicolas A.,CNRS Laboratory for Microelectronics Technolgy | Aranda-Espinoza S.,Aix - Marseille University | Bongrand P.,Aix - Marseille University | Limozin L.,Aix - Marseille University
Biophysical Journal | Year: 2011

The binding properties of biomolecules play a crucial role in many biological phenomena, especially cell adhesion. Whereas the attachment kinetics of soluble proteins is considered well known, complex behavior arises when protein molecules are bound to the cell membrane. We probe the hidden kinetics of ligand-receptor bond formation using single-molecule flow chamber assays and Brownian dynamics simulations. We show that, consistent with our recently proposed hypothesis, association requires a minimum duration of contact between the reactive species. In our experiments, ICAM-1 anchored on a flat substrate binds to anti-ICAM-1 coated onto flowing microbeads. The interaction potential between bead and substrate is measured by microinterferometry and is used as an ingredient to simulate bead movement. Our simulation calculates the duration of ligand-receptor contacts imposed by the bead movement. We quantitatively predict the reduction of adhesion probability measured for shorter tether length of the ligand or if a repulsive hyaluronan layer is added onto the surface. To account for our results, we propose that bond formation may occur in our system by crossing of a diffusive plateau in the energy landscape, on the timescale of 5 ms and an energy barrier of 5 k BT, before reaching the first detectable bound state. Our results show how to relate cell-scale behavior to the combined information of molecular reactivity and biomolecule submicron-scale environment. © 2011 by the Biophysical Society.

Otsuka I.,Joseph Fourier University | Tallegas S.,Joseph Fourier University | Tallegas S.,CNRS Laboratory for Microelectronics Technolgy | Sakai Y.,Joseph Fourier University | And 6 more authors.
Nanoscale | Year: 2013

The present paper describes the orientational control of 10 nm scale cylinders in sugar-based block copolymer thin films by simply varying the composition of the annealing co-solvent. The affinity of the block copolymer to the solvent vapor could be systematically adjusted in this way. © The Royal Society of Chemistry 2013.

Pietroy D.,CNRS Laboratory for Microelectronics Technolgy | Gereige I.,Solar and Photovoltaic Engineering Research Center | Gourgon C.,CNRS Laboratory for Microelectronics Technolgy
Microelectronic Engineering | Year: 2013

Transmission scatterometry is studied as a characterization tool for gratings nanoimprinted in a resist layer spincoated on the top of a transparent substrate. In this case, the larger part of the incident signal is transmitted which can make the reflection analysis harder. Although the backward reflections in the substrate induce an error which is difficult to correct, results are shown to be in good agreement with SEM measurements and reflection mode scatteromerty. © 2013 Elsevier B.V. All rights reserved.

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