Couches conductrices par voie organométallique pour les dispositifs 3D en microélectronique

La recherche de nouvelles techniques de métallisation d'interconnexion 3D est nécessaire dans le cadre d'une miniaturisation de plus en plus accrue des dispositifs électroniques. De nouvelles techniques de métallisation en voie liquide reposant sur la chimie organométallique de complexes amidinate ont été optimisées. Ces procédés assurent la formation de couches fonctionnelles de silicate de manganèse jouant le rôle de barrière de diffusion et de couche conductrice de cuivre dans des structures 3D. Les mécanismes de dépôt ont été étudiés et révèlent la formation de nanoparticules métastables de cuivre au cours d'un dépôt par OMCLD. Par la suite, l'ajout d'une faible quantité d'un agent stabilisant additionnel (hexadécylamine), au cours de l'hydrogénolyse du précurseur, assure la stabilité de nano-icosaèdre et de nano-décaèdre métallique de cuivre. La comparaison des réponses plasmoniques expérimentales et simulées a permis de suivre la croissance de clusters d'oxyde de cuivre et de faire correspondre un plasmon localisé à 600 nm avec une monocouche complète d'oxyde en surface des nanoparticules. Enfin, la réponse plasmonique de nanocristaux d'argent a permis d'étudier les interactions dynamiques à l'interface entre la particule et son milieu environnant.The research of new techniques of metallization for 3D silicon integration is necessary in the context of the constant miniaturization of electronics devices. A new liquid path metallization technique, based on organometallic chemistry of amidinate complexes, has been optimized in this work. These processes ensure the formation of functional layers of manganese silicate playing the role of barrier layer as well as the formation of copper films in 3D silicon structures. The deposition mechanisms have been studied and the key role of metastable copper nanoparticles during the OMCLD process is evidenced. Thereafter, an addition of a small amount of an additional stabilizing agent (hexadecylamine), during the hydrogenolysis of the precursor leads the stability of pure copper nano-icosahedron and nano-decahedron. The comparison between experimental and simulated plasmonic responses has permitted to follow the growth of copper oxide clusters on copper nanocrystals. The results indicate that a localized plasmon at 600 nm corresponds with a complete copper oxide monolayer. Finally, the plasmonic response of silver nanocrystals was used to study the dynamic interactions of organic ligands at the interface between the particle and its surrounding medium

Conductive layers by organometallic process for 3D devices in microelectronic

La recherche de nouvelles techniques de métallisation d’interconnexion 3D est nécessaire dans le cadre d’une miniaturisation de plus en plus accrue des dispositifs électroniques. De nouvelles techniques de métallisation en voie liquide reposant sur la chimie organométallique de complexes amidinate ont été optimisées. Ces procédés assurent la formation de couches fonctionnelles de silicate de manganèse jouant le rôle de barrière de diffusion et de couche conductrice de cuivre dans des structures 3D. Les mécanismes de dépôt ont été étudiés et révèlent la formation de nanoparticules métastables de cuivre au cours d’un dépôt par OMCLD. Par la suite, l’ajout d’une faible quantité d’un agent stabilisant additionnel (hexadécylamine), au cours de l’hydrogénolyse du précurseur, assure la stabilité de nano-icosaèdre et de nano-décaèdre métallique de cuivre. La comparaison des réponses plasmoniques expérimentales et simulées a permis de suivre la croissance de clusters d’oxyde de cuivre et de faire correspondre un plasmon localisé à 600 nm avec une monocouche complète d’oxyde en surface des nanoparticules. Enfin, la réponse plasmonique de nanocristaux d’argent a permis d’étudier les interactions dynamiques à l’interface entre la particule et son milieu environnant.The research of new techniques of metallization for 3D silicon integration is necessary in the context of the constant miniaturization of electronics devices. A new liquid path metallization technique, based on organometallic chemistry of amidinate complexes, has been optimized in this work. These processes ensure the formation of functional layers of manganese silicate playing the role of barrier layer as well as the formation of copper films in 3D silicon structures. The deposition mechanisms have been studied and the key role of metastable copper nanoparticles during the OMCLD process is evidenced. Thereafter, an addition of a small amount of an additional stabilizing agent (hexadecylamine), during the hydrogenolysis of the precursor leads the stability of pure copper nano-icosahedron and nano-decahedron. The comparison between experimental and simulated plasmonic responses has permitted to follow the growth of copper oxide clusters on copper nanocrystals. The results indicate that a localized plasmon at 600 nm corresponds with a complete copper oxide monolayer. Finally, the plasmonic response of silver nanocrystals was used to study the dynamic interactions of organic ligands at the interface between the particle and its surrounding medium

Dimeric Gold Bis(carbene) Complexes by Transmetalation in Water

International audienceDue to its cost, environmental benefits, and safety advantages, water has become more and more important as a solvent for catalytic reactions and constitutes the best environment for biomedical applications. Therefore, water-soluble and water-stable metal complexes containing strong σ-donor ligands such as N-heterocyclic carbenes (NHCs) are of great interest in modern coordination chemistry. In this paper we present the successful preparation of two new dinuclear gold(I)–bis(NHC) complexes in water, by applying the Ag–NHC transfer route. This green synthetic strategy is valuable for gold(I) compounds involving N-functionalized neutral and dianionic bis(NHC) ligands. These two water-soluble compounds were analyzed by spectroscopic methods and by X-ray diffraction. Furthermore, ab initio and DFT calculations on the corresponding dinuclear gold complexes illustrate the important influence of the electrostatic environment of the dinuclear entity on the aurophilic interactions and help to understand the molecular arrangement presented in this paper

Integration of Gold Nanoparticles to Modulate the Ignitability of Nanothermite Films

International audienceThermite multilayered films composed of alternating thin layers of metal/oxidizers have various uses in microelectromechanical systems (MEMS), microelectronics and materials bonding applications. Recently, applied research especially on the micro-initiator applications has engendered an urgent need to improve ignitability without changing the layering, reactant spacing that both affect the combustion characteristics. This work describes an innovative nano-engineering solution to reduce the energy barriers for mass transport making it possible to substantially lower ignition energy of CuO/Al reactive multilayers without manipulating the fuel and oxide layers thickness. To that end, gold nanoparticles exhibiting high thermal diffusivity properties are in-situ grown uniformly inside the first CuO layer to produce localized hot-spot

Deciphering ligands’ interaction with Cu and Cu2O nanocrystal surfaces by NMR solution tools

International audienceThe hydrogenolysis of [Cu2(iPrN)2(CCH3)2] in the presence of hexadecylamine (HDA) or tetradecylphosphonic acid (TDPA) in toluene leads to 6–9 nm copper nanocrystals. Solution NMR spectroscopy has been used to describe the nanoparticle surface chemistry during the dynamic phenomenon of air oxidation. The ligands are organized as multilayered shells around the nanoparticles. The shell of ligands is controlled by both their intermolecular interactions and their bonding strength on the nanocrystals. Under ambient atmosphere, the oxidation rate of colloidal copper nanocrystals closely relies on the chemical nature of the employed ligands (base or acid). Primary amine molecules behave as soft ligands for Cu atoms, but are even more strongly coordinated on surface CuI sites, thus allowing a very efficient corrosion protection of the copper core. On the contrary, the TDPA ligands lead to a rapid oxidation rate of Cu nanoparticles and eventually to the re-dissolution of CuII species at the expense of the nanocrystals

Cross-over study of electric and electronic properties versus microstructure of MOCVD processed TiO2 anatase films for solar water splitting

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The role of alkylamine in the stabilization of CuO nanoparticles as a determinant of the Al/CuO redox reaction

International audienceWe report on a new strategy to synthesize Al/CuO nanothermites from commercial Al and ultra-small chemically synthesized CuO nanoparticles coated with alkylamine ligands. These usual ligands stabilize the CuO and prevent them from aggregation, with the goal to enhance the interfacial contact between Al and CuO particles. Using a variety of characterization techniques, including microscopy, spectroscopy, mass spectrometry and calorimetry (ATG/DSC), the structural and chemical evolution of CuO nanoparticles stabilized with alkylamine ligands are analyzed upon heating. This enables us to depict the main decomposition processes taking place at the CuO surface at low temperature (< 500 °C): the ligands fragment into organic species accompanied with H2O and CO2 release, which promotes the CuO reduction into Cu2O and further Cu. We quantitatively discuss these chemical processes highlighting for the first time the crucial importance of synthesis conditions that control the chemical purity of the organic ligands (octylamine molecules and derivatives such as carbamate and ammonium ions) on the nanothermite performances. From these findings, an effective method to overcome the ligands-induced CuO degradation at low temperature is proposed and Al/CuO nanothermite reaction is analyzed, in terms of onset temperature and energy released. We produce original structures composed of aluminium nanoparticles embedded in CuO grainy matrixes exhibiting onset temperature ~200 °C below usual Al/CuO onsets, having specific combustion profiles depending on synthesis conditions, while preserving the total amount of energy released

Structure and Chemical Characterization at the Atomic Level of Reactions in Al/CuO Multilayers

International audienceSputter-deposited Al/CuO multilayers exhibit fast combustion reactions in which an exothermic chemical reaction wave -controlled by the migration of oxygen atoms from the oxide matrix towards the aluminum layers through interfacial layers- moves throughout the multilayer at subsonic rates (m/s to tens of m/s). We directly observed the structural and chemical evolution of Al/CuO/Al multilayers upon heating to 700 °C using high-magnification Transmission Electron Microscopy (TEM) and Scanning TEM (STEM), providing simultaneous sub-nanometrer imaging resolution and detailed chemical analysis. Interestingly, as deposited, the trilayer is characterized by two distinct interfacial layers: 4.1 ± 0.2 nm thick amorphous alumina and 15 ± 5 nm thick mixture of AlOx and CuxAlyOz, at the bottom interface and top interface respectively. Upon heating, we accurately characterized the evolving nature and structure of these interfaces which are rapidly replaced by the reaction terminal oxide (Al2O3). For the first time, we unraveled the release of gaseous O from the sparse columnar and defective CuO well below reaction onset (at ~200 °C) which accumulates at interfaces and contributes to initiate the Al oxidation process at the vicinity of native interfaces. The oxidation process is demonstrated to be accompanied by a continuous densification and modification of the CuO layer. Between 300 - 350 °C, we observed a brutal shrinkage of CuO layer (14% loss of its initial thickness) leading to the mechanical fracture in the top alumina growing layer. Consequently, this latter becomes highly permeable to oxygens leading to a brutal enhancement of the oxidation rate (× 4). We also characterized stressed-induced interfacial delamination at 500 °C pointing clearly mechanical fragility of the top interface after the CuO transformation. Altogether, these results permit to establish a multi-step reaction scenario in Al/CuO sputter-deposited films supporting to an unprecedented level a mechanistic assignation of Differential Scanning Calorimetry (DSC) peaks. This study offers potential benefits for the development of aging models enabling the virtual prediction of the calorimetric response of exothermic Al/CuO thin film reactions