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Ultra-thin films and multigate devices architectures for future CMOS scaling

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Science China(Information Sciences) 2011年第5期54卷 990-1003页

作者： DELEONIBUS Simon cea-leti MINATEC Campus Grenoble France

The nanoelectronics industry is facing historical challenges to scale down CMOS devices to meet demands for low voltage, low power, high performance and increased functionality. Using new materials and devices architectures is necessary. HiK gate dielectrics and metal gates have been introduced and have shown their ability to reduce power consumption. Fully depleted ultra-thin SOI devices are a good alternative to bulk for low power applications. Multigate devices are the current goal in device architecture to increase MOSFET drivability, reduce power, and allow new opportunities for future applications. Thin film based solutions will be necessary in the future because of fundamental limitations on gate capacitance scaling and system integration requirements. Exploiting 3D device stacking via wafer bonding could be a good way to introduce new materials (HiK, strained Si, hybrid orientations, Ge, III-Vs, Carbon-based materials, graphene and CNTs, and functional molecules) and continue increasing integration density. Si based CMOS will be scaled beyond the ITRS as the System-on-Chip/Wafer Platform.

关键词： CMOSFETs silicon strain carbon germanium silicon on insulator technology FDSOI FinFET multigates nanowires wafer bonding 3D sequential integration

Lights for epilepsy:can photobiomodulation reduce seizures and offer neuroprotection?

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Neural Regeneration Research 2023年第7期18卷 1423-1426页

作者： Napoleon Torres-Martinez Stephan Chabardes John Mitrofanis University of Grenoble Alpes FDD and CEA-LETIClinatecGrenobleFrance

Epilepsy is synonymous with individuals suffering repeated“fits”or *** seizures are triggered by bursts of abnormal neuronal activity,across either the cerebral cortex and/or the *** addition,the seizure sites are characterized by considerable neuronal *** the factors that generate this abnormal activity and death are not entirely clear,recent evidence indicates that mitochondrial dysfunction plays a central *** treatment options include drug therapy,which aims to suppress the abnormal neuronal activity,or surgical intervention,which involves the removal of the brain region generating the seizure ***,~30%of patients are unresponsive to the drugs,while the surgery option is invasive and has a morbidity ***,there is a need for the development of an effective non-pharmacological and non-invasive treatment for this disorder,one that has few side *** this review,we consider the effectiveness of a potential new treatment for epilepsy,known as photobiomodulation,the use of red to near-infrared light on body *** studies in animal models have shown that photobiomodulation reduces seizure-like activity and improves neuronal ***,it has an excellent safety record,with little or no evidence of side effects,and it is *** all together,this treatment appears to be an ideal treatment option for patients suffering from epilepsy,which is certainly worthy of further consideration.

关键词： cell death gliosis inflammation infrared mitochondria non-pharmacological red seizure

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Hard carbon derived from cellulose as anode for sodium ion batteries:Dependence of electrochemical properties on structure

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Journal of Energy Chemistry 2016年第5期25卷 761-768页

作者： V.Simone A.Boulineau A.de Geyer D.Rouchon L.Simonin *** Univ. Grenoble Alpes cea LITEN cea INAC cea LETI

Cellulose, the most abundant organic polymer on Earth, is a sustainable source of carbon to use as a negative electrode for sodium ion batteries. Here, hard carbons(HC) prepared by cellulose pyrolysis were investigated with varying pyrolysis temperature from 700 °C to 1600 °C. Characterisation methods such as Small Angle X-ray Scattering(SAXS) measurements and N2adsorption were performed to analyse porosity differences between the samples. The graphene sheet arrangements were observed by transmission electron microscopy(TEM): an ordering of the graphene sheets is observed at temperatures above 1150 °C and small crystalline domains appear over 1400 °C. As the graphene sheets start to align, the BET surface area decreases and the micropore size increases. To correlate hard carbon structures and electrochemical performances, different tests in Na//HC cells with 1 M NaPF6ethylene carbonate/dimethyl carbonate(EC/DMC) were performed. Samples pyrolysed from 1300 °C to 1600 °C showed a 300 m Ah/g reversible capacity at C/10 rate(where C = 372 mA/g) with an excellent stability in cycling and a very good initial Coulombic efficiency of up to 84%. Furthermore, hard carbons showed an excellent rate capability where sodium extraction rate varies from C/10 to 5C. At 5C more than 80% of reversible capacity remains stable for hard carbons synthesized from 1000 °C to 1600 °C.

关键词： Sodium ion battery Anode Hard carbon Structure

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2.45 GHz 0.8 mW voltage-controlled ring oscillator （VCRO） in 28 nm fully depleted silicon-on-insulator （FDSOI） technology

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Frontiers of Materials Science 2015年第2期9卷 156-162页

作者： Gilles JACQUEMOD Alexandre FONSECA Emeric de FOUCAULD Yves LEDUC Philippe LORENZINI EpOC URE UNS 006 Universite Nice Sophia Antipolis Sophia Antipolis France cea-leti Grenoble France

MOS bulk transistor is reaching its limits： sub-threshold slope （SS）, drain induced barrier lowering （DIBL）, threshold voltage （VT） and VDD scaling slowing down, more power dissipation, less speed gain, less accuracy, variability and reliability issues. Fully depleted devices are mandatory to continue the technology roadmap. FDSOI technology relies on a thin layer of silicon that is over a buried oxide （BOx）. Called ultra thin body and buried oxide （UTBB） transistor, FDSOI transistors correspond to a simple evolution from conventional MOS bulk transistor. The capability to bias the back-gate allows us to implement calibration techniques without adding transistors in critical blocks. We have illustrated this technique on a very low power voltage-controlled oscillator （VCO） based on a ring oscillator （RO） designed in 28 nm FDSOI technology. Despite the fact that such VCO topology exhibits a larger phase noise, this design will address aggressively the size and power consumption reduction. Indeed we are using the efficient back-gate biasing offered by the FDSOI MOS transistor to compensate the mismatches between the different inverters of the ring oscillator to decrease jitter and phase noise. We will present the reasons which led us to use the FDSOI technology to reach the specifications of this PLL. The VCRO exhibits a 0.8 mW power consumption, with a phase noise about -94 dBc/Hz@l MHz.

关键词： nanoelectronics FDSOI UTBB VCO PLL

Coherence of the Even-Odd Rule with an Effective-Valence Isoelectronicity Rule for Chemical Structural Formulas: Application to Known and Unknown Single-Covalent-Bonded Compounds

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Open Journal of Physical Chemistry 2014年第3期4卷 126-133页

作者： Geoffroy Auvert cea-leti Grenoble France

Ions or molecules are said to be isoelectronic if they are composed of different elements but have the same number of electrons, the same number of covalent bonds and the same structure. This criterion is unfortunately not sufficient to ensure that a chemical structure is a valid chemical compound. In a previous article, a procedure has been described to draw 2D valid structural formulas: the even-odd rule. This rule has been applied first to single-bonded molecules then to single-charged single-bonded ions. It covers hypovalent, hypervalent or classic Lewis’ octet compounds. The funding principle of the even-odd rule is that each atom of the compound possesses an outer-shell filled only with pairs of electrons. The application of this rule guarantees validity of any single-covalent-bond chemical structure. In the present paper, this even-odd rule and its electron-pair criterion are checked for coherence with an effective-valence isoelectronic rule using numerous known compounds having single-covalent-bond connections. The test addresses Lewis’ octet ions or molecules as well as hypovalent and hypervalent compounds. The article concludes that the even-odd rule and the effective-valence isoelectronicity rule are coherent for known single-covalent-bond chemical compounds.

关键词： Isoelectronicity Effective Valence Molecule Ion Even-Odd Rule Structural Formula Covalent Bond

Chemical Structural Formulas of Single-Bonded Ions Using the “Even-Odd” Rule Encompassing Lewis’s Octet Rule: Application to Position of Single-Charge and Electron-Pairs in Hypo- and Hyper-Valent Ions with Main Group Elements

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Open Journal of Physical Chemistry 2014年第2期4卷 67-72页

作者： Geoffroy Auvert cea-leti Grenoble France

Lewis developed a 2D-representation of molecules, charged or uncharged, known as structural formula, and stated the criteria to draw it. At the time, the vast majority of known molecules followed the octet-rule, one of Lewis’s criteria. The same method was however rapidly applied to represent compounds that do not follow the octet-rule, i.e. compounds for which some of the composing atoms have greater or less than eight electrons in their valence shell. In a previous paper, an even-odd rule was proposed and shown to apply to both types of uncharged molecules. In the present paper, the even-odd rule is extended with the objective to encompass all single-bonded ions in one group: Lewis’s ions, hypo- and hypervalent ions. The base of the even-odd representation is compatible with Lewis’s diagram. Additionally, each atom is subscripted with an even number calculated by adding the valence number, the number of covalent bonds of the element, and its electrical charge. This paper describes how to calculate the latter number and in doing so, how charge and electron-pairs can actually be precisely localized. Using ions known to be compatible with Lewis’s rule of eight, the even-odd rule is compared with the former. The even-odd rule is then applied to ions known as hypo- or hypervalent. An interesting side effect of the presented rule is that charge and electron-pairs are unambiguously assigned to one of the atoms composing the single-charged ion. Ions that follow the octet rule and ions that do not, are thus reconciled in one group called “electron-paired ions” due to the absence of unpaired electrons. A future paper will focus on the connection between the even-odd rule and molecules or ions having multiple bonds.

关键词： Charge Molecule Ion Even-Odd Rule Structural Formula Octet Rule Single Bond Covalent

The Even-Odd Rule on Single Covalent-Bonded Structural Formulas as a Modification of Classical Structural Formulas of Multiple-Bonded Ions and Molecules

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Open Journal of Physical Chemistry 2014年第4期4卷 173-184页

作者： Geoffroy Auvert cea-leti Grenoble France

In organic chemistry, as defined by Abegg, Kossel, Lewis and Langmuir, compounds are normally represented using structural formulas called Lewis structures. In these structures, the octet rule is used to define the number of covalent bonds that each atom forms with its neighbors and multiple bonds are frequent. Lewis’ octet rule has unfortunately shown limitations very early when applied to non-organic compounds: most of them remain incompatible with the “rule of eight” and location of charges is uncertain. In an attempt to unify structural formulas of octet and non-octet molecules or single-charge ions, an even-odd rule was recently proposed, together with a procedure to locate charge precisely. This even-odd rule has introduced a charge-dependent effective-valence number calculated for each atom. With this number and the number of covalent bonds of each element, two even numbers are calculated. These numbers are both used to understand and draw structuralformulas of single-covalent-bonded compounds. In the present paper, a procedure is proposed to adjust structural formulas of compounds that are commonly represented with multiple bonds. In order to keep them compatible with the even-odd rule, they will be represented using only single covalent bonds. The procedure will then describe the consequences of bond simplification on charges locations. The newly obtained representations are compared to their conventional structural formulas, i.e. single-bond representation vs. multiple-bond structures. Throughout the comparison process, charges are precisely located and assigned to specific atoms. After discussion of particular cases of compounds, the paper finally concludes that a rule limiting representations of multiplecovalent bonds to single covalent bonds, seems to be suitable for numerous known compounds.

关键词： Multiple Bond Single Bond Covalent Bond Molecule Ion Even-Odd Rule Structural Formula

Progress Toward Steady-State Operation on Tore Supra

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Plasma Science and Technology 2004年第1期6卷 2101-2108页

作者： J.Jacquinot G.T.Hoang on behalf of the Tore Supra Team Euratom-cea Association CEA/DSM/DRFC CEA Cadarache F-13108 Saint-Paul-Lez-Durance FranceEuratom-CEA Association CEA/DSM/DRFC CEA Cadarache F-13108 Saint-Paul-Lez-Durance FranceEuratom-CEA Association CEA/DSM/DRFC CEA Cadarache F-13108 Saint-Paul-Lez-Durance France

Important technological and physics issues related to steady-state operationrequired for next step are being examined on Tore Supra, after a major upgrade of internalcomponents in order to increase the heat extraction capability to 25 MW for 1000 s. Here, we showfirst experimental results, where all the plasma facing components were actively cooled duringpulses exceeding four minutes, with reactor-relevant heat load. New physics was observed innon-inductively driven plasmas, including a stationary peaked radial profile of the plasma densitygenerated by an anomalous inward pinch; and a regime characterized by sinusoidal oscillations ofcentral electron temperature, governed by non-linear coupling between heat transport and plasmacurrent analogous to a predator-prey mechanism.

关键词： steady-state operation tore supra, non-inductively driven plasma

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How the Even-Odd Rule, by Defining Electrons Pairs and Charge Positions, Can Be Used as a Substitute to the Langmuir-Octet Rule in Understanding Interconnections between Atoms in Ions and Molecules

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Open Journal of Physical Chemistry 2015年第2期5卷 28-38页

作者： Geoffroy Auvert cea-leti Grenoble Alps University Grenoble France

In the course of time, numerous rules were proposed to predict how atoms connect through covalent bonds. Based on the classification of elements in the periodic table, the rule of eight was first proposed to draw formulas of organic compounds. The later named octet rule exhibited shortcomings when applied to inorganic compounds. Another rule, the rule of two, using covalent bonds between atoms, was proposed as an attempt to unify description of organic and inorganic molecules. This rule unfortunately never managed to expand the field of application of the octet rule to inorganic compounds. In order to conciliate organic and inorganic compounds, the recently put forward even-odd and the isoelectronicity rules suggest the creation of one group of compounds with pairs of electrons. These rules compass the rule of two for covalent bonds as well as the octet rule for organic compounds and suggest transforming bonds of multi-bonded compounds in order to unify representations of both groups of compounds. The aim of the present paper is fourfold: to extend the rule of two to every atom shells;to replace the well-known octet rule by the even-odd rule;to apply the isoelectronicity rule to each atom and to reduce the influence range of the charge of an atom in a compound. According to both rules, the drawing of one atom with its single-covalent bonds is described with electron pairs and charge positions. To illustrate the rules, they are applied to 3D configurations of clusters.

关键词： Even-Odd Isoelectronicity Rule Effective Valence Molecule Chemical Formula Covalent Bond Ion