Vincent Rouessac

French National Centre for Scientific Research | CNRS · Institut Européen des Membranes (UMR5635)

Due to their polymorphism, TiO2 films are quintessential components of state-of-the-art functional materials and devices for various applications from dynamic random access memory to solar water splitting. However, contrary to other semiconductors/dielectric materials, the relationship between structural/morphological and electrical properties at t...

Phosphonic acid-based membranes were prepared by Plasma Enhanced Chemical Vapor Deposition (PECVD) with an input power of 100 W in a continuous or pulsed glow discharge. Comparing both kinds of plasma discharges makes appear that the pulsed configuration gives rise to PECVD materials with longer hydrocarbon chains and thus higher flexible polymer n...

The barrier properties of the technologically attractive amorphous silica films depend on their structural characteristics at the atomic level, which, in turn are strongly influenced by the deposition conditions. In this paper, we propose an investigation of the poorly investigated densification mechanism of amorphous SiO 2 films processed by CVD f...

Green H2 production by solar water splitting relies entirely on the intrinsic properties of the photocatalyst. In this study the impact of these intrinsic properties on the photocatalytic activity of anatase TiO2, the quintessential component of state of the art photocatalytic systems was explored at the nanoscale. The exploration involved a holist...

Previously optimized anatase and nitrogen-doped anatase TiO2 coatings have been grown by low-frequency plasma-enhanced chemical vapor deposition (PECVD) on different kinds of substrates at low plasma power (64 W) and high plasma power (100 W) for photo-electrochemical studies. Nitrogen-doped TiO2 layers exhibit better photoactivity and also higher...

Previously optimized anatase and nitrogen-doped anatase TiO2 coatings have been grown by low-frequency plasma-enhanced chemical vapor deposition (PECVD) on different kinds of substrates at low plasma power (64 W) and high plasma power (100 W) for photo-electrochemical studies. Nitrogen-doped TiO2 layers exhibit better photoactivity and also higher...

Among the electrolyte membranes for proton conduction in hydrogen production systems and fuel cells, phosphonic acid-based membranes are promising because of their advantage as good proton conductors in anhydrous medium which allows their use in systems operating at high temperature (80–150 °C) which is not the case of sulfonic acid-based ones such...

This study aims at assessing the use of a quartz crystal microbalance (QCM) coupled with an adsorption system to measure water vapor transfer properties in micrometric size cellulose particles. This apparatus allows measuring successfully water vapor sorption kinetics at successive relative humidity (RH) steps on a dispersion of individual micromet...

Plasma processes, initially developed for microelectronics in the 1950s, represent a clean and very flexible technology which has been used in many fields of materials chemistry since the 1980s. The potentialities of plasma processes in modifying or depositing thin layers on material’s surface are exceptionally broad, hence the increasing interest...

Due to their good chemical and thermal inertness, SiCxNy:H films are suitable for a variety of applications in electronic, tribology, optic, photovoltaic and more recently gas separation membranes. For these applications, film evolution can be attractively probed by FTIR spectroscopy. In this work, a systematic quantum mechanical study of the vibra...

A one-step low-frequency Plasma Enhanced Chemical Vapor Deposition (PECVD) process, operating at temperature as low as 350 °C, has been implemented to prepare single-oriented pure and N-doped anatase films. The layers have been synthesized using titanium isopropoxide as a precursor, and NH3 as a doping agent. Optimized PECVD conditions have enabled...

Porous low-k materials used as insulator for interconnection levels in CMOS devices, are easily damaged during the patterning processes. Pore size characterization after material damage is challenging due to the chemical modification induced by the applied process. Numerical simulation of solvent adsorption on silica and functionalized silica surfa...

The impact of plasma reactive ion etching on hybrid organic/inorganic polymer materials is investigated in detail regarding chemical (composition) and physical (porosity) aspects. Porous low dielectric constant insulating films are used in integrated circuits and these experience plasma etching before the deposition of conductive copper lines. We s...

In this work, low frequency PECVD a- SiCxNy:H thin films have been synthesized in the temp. range 25- 300 °C from hexamethyldisilazane precursor mixed with ammonia at various concns. A relevant correlation has been evidenced between the [N] /[C] at. ratio in the gaseous phase and in the deposited thin films, allowing both prediction and control of...

In this work the long-term antibacterial activity of silver doped titania coating is studied systematically as a function of the titania layer structure (with and without molecular template) and the amount and physical properties of the silver dopant. Silver was incorporated in two different ways into the titania sol-gel film, either by co-depositi...

Amorphous non-oxide a-SiCxNy:H thin films have been synthesized at 300 or 500 K from an Ar/HMDSN/NH3 gas mixture in a lab-scale microwaves PECVD reactor. These thin films have been characterized by FTIR spectroscopy and spectroscopic ellipsometry coupled with gas adsorption, in order to evidence the influence of PECVD synthesis conditions on the ma...

This study aims to investigate the modified surface porosity of SiOCH low-k porous thin films using statistical mechanics molecular simulations and ellipso-porosimetry. The thin films are modified by plasma etching and wet cleaning. Numerical simulations of solvent adsorption on surfaces highlighted solvent affinity variations depending on chemical...

We show that Derjaguin’s theory of adsorption can be used to predict adsorption on bare and modified surfaces using parameters available to simple experiments. Using experiment and molecular simulation of adsorption of various gases on hydroxylated, methylated, and trifluoromethylated silica, this simple parametrization of Derjaguin’s model allows...

https://hal.archives-ouvertes.fr/hal-01122896

The fluorescence of thin films of a diimine-substituted phenyleneethynylene compound can be efficiently quenched by nitroaromatic vapors, which is not the case for the unsubstituted parent compound. Thin-film porosity is usually considered to be an essential factor for efficient quenching, but in the present case the origin of the quenching is comp...

Remarkable properties of plasma polymer films are greatly dependent not only on the chemical structure of precursor but also on the reactor design and the deposition conditions. In many industrial applications it is a challenge to control the plasma polymer structure. In this paper we investigate the chemical transformation of various aromatic comp...

The impact of plasma etching and chemical wet cleaning on solvent diffusion in porous network of a SiOCH low-k dielectric material is studied. Characterization of porosity and pore size distribution by means of ellipso-porosimetry and positron annihilation lifetime spectroscopy are presented. The results are compared with solvent diffusion kinetics...

La porosité des matériaux peut être caractérisée par ellipso-porosimétrie (EP), méthode optique couplée à l’adsorption de solvants. Afin d'améliorer la précision de cette méthode pour des micropores (d < 2nm), des isothermes d’adsorption de référence doivent être obtenues. Pour cela, des expériences d’EP et des simulations moléculaires Monte-Carlo...

We explore for the first time the ability of a three-dimensional polyacrylonitrile/gold material prepared by a low-cost and scalable synthesis method, based on the combination of electrospinning and sputtering, as a new material with large surface area to provide high loadings of enzymes to enhance the electrochemical performances of enzyme electro...

A study of transmittance and photoluminescence spectra on the growth of oxygen-rich ultra-thin ZnO films prepared by atomic layer deposition is reported. The structural transition from an amorphous to a polycrystalline state is observed upon increasing the thickness. The unusual behavior of the energy gap with thickness reflected by optical propert...

Proceedings available here: http://www.sematech.org/meetings/archives/3d/

Constitutional mesoporous thin-layer electrodes have been used to generate confined fullerene wires allowing a capacitive diffusion of electrons.

Si–Zr–C–N membranes were studied for an application of hydrogen separation at high temperature. The synthesis of single-source molecular precursor incorporating four elements Si, Zr, C and N in the same molecule has been developed leading to a volatile compound that can be deposited in a gaseous way by plasma enhanced chemical vapor deposition. The...

A study of transmittance and photoluminescence spectra on the growth of oxygen-rich ultra-thin ZnO films prepared by atomic layer deposition is reported. The structural transition from an amorphous to a polycrystalline state is observed upon increasing the thickness. The unusual behavior of the energy gap with thickness reflected by optical propert...

Proceedings available here: http://www.sematech.org/meetings/archives/3d/

Hydrophobic mesostructured organosilica-based thin films with tunable mesoporosity offer promising opportunities for ultra low k applications. They are presently prepared by spin-on solutions and evaporation-induced self-assembly method (EISA) using polystyrene-b-polyethylene oxide block copolymers as structure-directing agents and methyltriethoxys...

Thin films of organosilicon materials produced by plasma-assisted deposition are frequently used because of their multifunctional character, but few comparative studies into their growth on structured surfaces are available. Two types of CVD processes, plasma-enhanced (PE)CVD and remote plasma-enhanced (RPE)CVD are taken as typical operating condit...

Plasma-enhanced (PE)CVD is used to create, in a single step, a superhydrophobic (SH) (water contact angle over 150°) layer starting from hexamethyldisiloxane (HMDSO) vapor (i.e., without fluorine) in a low-frequency, capacitively coupled plasma reactor under low pressure. Several SH microstructures are obtained, depending on experimental parameters...

Sol–gel routes are often investigated and adapted to prepare, by suitable chemical modifications, submicronic powders and derived materials with controlled morphology, which cannot be obtained by conventional solid state chemistry paths. Wet chemistry methods provide attractive alternative routes because mixing of species occurs at the atomic scale...

In this work, hydrophobic mesostructured organosilica thin films, exhibiting isolated mesopores (~ 7 nm), have been successfully deposited by spin-coating using different polystyrene-block-polyethylene oxide copolymers (PS-b-PEO) as structure-directing agents and methyltriethoxysilane (MTES) as organosilica precursor. Different ordered mesostructur...

For using as separative membranes based on magnetic selectivity, nanoporous ferrimagnetic membranes of maghemite (γ-Fe2O3) and cobalt ferrite (Fe2CoO4) were prepared by the sol-gel route from ferrofluid colloidal solutions. Their magnetic properties were examined by superconductor quantum interference device (SQUID), and their structures and porous...

Silicon carbonitride thin films have been deposited by plasma enhanced chemical vapor deposition (PECVD) from bis(dimethylamino)dimethylsilane (BDMADMS) as a function of X=(BDMADMS/(BDMADMS+NH3)) between 0.1 and 1, and plasma power P (W) between 100 and 400W. The microstructure of obtained materials has been studied by SEM, FTIR, EDS, ellipsometrie...

In this study, SiOCH films for gas separation were prepared on a mixed cellulose ester (MCE) substrate by means of plasma-enhanced chemical vapor deposition (PECVD) using octamethylcyclotetrasiloxane (OMCTS) as a precursor. The RF power was the major variable in adjusting the pore structure of the SiOCH film. The FTIR analysis showed that there was...

In this study, Doppler broadening energy spectroscopy (DBES) combined with slow positron beam was used to discuss the effect of substrate types on the fine structure of a plasma-polymerized SiOCH layer as a function of depth. From the SEM pictures, the SiOCH films formed on different substrates showed hemispherical macrostructures, and the depositi...

We have developed chemical sensors based on strong modifications of rubrene nanocrystals fluorescence decays under different chemical surroundings. These nanocrystals were grown in silicate sol–gel thin films. To improve the nanosensors selectivity, we used alkoxide mixtures of (TMOS: tetramethoxysilane, MTMOS: methyltrimethoxysilane and TMSE: 1,2-...

Plasma processes, initially developed for microelectronics in the 1950s, represent a clean and very flexible technology which has been used in many fields of materials chemistry since the 1980s. The potentialities of plasma processes in modifying or depositing thin layers on materials surface are exceptionally broad; hence the increasing interest i...

Plasma processes, initially developed for micro-electronics in the fifties, represent a clean and very flexible technology which has been used in many fields of the materials chemistry since the eighties. The potentialities of plasma processes in modifying or depositing thin layers on materials surface are exceptionally broad, hence their increasin...

The ammonia absorption properties of polyaniline elaborated by the pulsed-plasma technique are studied. These properties depend on the structure of the polymer which is associated not only to plasma parameters such as peak power, ignition and extinction durations, pulse frequency and duty cycle, but also to the type of doping agent. Two methods of...

For 45nm and beyond microelectronics technology nodes, the integration of porous low dielectric constant (low-k) materials is now required to reach integrated dielectric constant values lower than 2.7. However, porous low-k materials have lower mechanical strength in comparison with traditional dense materials and are also affected by chemical diff...

An SiOxCyHz/mixed cellulose ester (MCE) composite membrane was fabricated by plasma deposition of hexamethyldisiloxane (HMDSO) monomer on the surface of an MCE substrate. The purpose is to apply the membrane for the oxygen enrichment of an O2/N2 mixture. The variation in the fine structure of the plasma-polymerized layers (SiOxCyHz) prepared at dif...

The development of microporous ceramic thin layers is of prime interest for sensors or gas separation membranes working at high temperature. Microporous silica membranes can be easily prepared by the sol–gel process. However the microporosity of pure silica is rapidly modified by steam at high temperature. One way to improve hydrothermal stability...

An SiOxCyHz/polycarbonate (PC) composite membrane was prepared via plasma deposition of tetraethoxysilane (TEOS) monomer on the surface of the PC substrate for the purpose of applying it in the pervaporation of an 80 wt.% aqueous tetrafluoropropanol (TFP) solution. The effects of plasma power and deposition time on the chemical and physical charact...

Plasma enhanced chemical vapor deposition (PECVD) a-SiCXNY:H thin films have been studied as molecular sieve membranes for light (hydrogen, helium) gas separation at room temperature up to 150°C. The microstructure of the deposited materials and their thermal stability have been characterized as a function of the electric plasma power and the ratio...

The penetration kinetics of different solvents having various properties (size, polarity, viscosityell) inside a porous low k SiOCH material modified by plasma treatments were investigated by ellipsometric porosimetry. The solvent penetration rates and durations to reach the saturation strongly depend on both the solvent properties and on the plasm...

In this study, the compatibility of "HF-Based" cleaning with porous low-k integration, and "pore-sealing" approach was investigated, and specific attention was paid to ultra low-k porosity evolution. We also tried to demonstrate if "k-recovery" could be achieved by thinning the modified surface layer in the pattern trench walls (plasma damaged laye...

This chapter discusses the basic principles and the recent advancement of microporous silica membrane. It discusses several inorganic membranes are available, focusing on the synthesis and applications of microporous amorphous silica membranes. Microporous amorphous silica exhibits a weak stability in aqueous solutions or wet streams, which limits...

Porous low k materials are used as insulator in integrated circuits interconnection levels. The impact of plasma post-treatments on such material was studied by neutron reflectometry coupled with deuterated solvents penetration. The porosity of the non-modified material determined by the CD3CD2OD adsorption isotherm is 28%. The CD3CD2OD and D2O dis...

We investigated the compatibility of "HF-Based" cleaning with porous low-k integration, and "pore-sealing" approach and specific attention was paid to ULK porosity evolution. We also tried to demonstrate if "k-recovery" could be achieved by thinning the modified surface layer in the pattern trench walls (plasma damaged layer).

This paper describes approaches developed for the preparation and also the characterization of innovative inorganic or hybrid membrane materials. Soft chemistry routes, sol–gel methods and plasma-enhanced chemical vapour deposition (PECVD) are used to get tailor-made layers with different architectures. The infiltrated composite membranes are first...

Three characterization techniques are described for studying the open nanoporosity, i.e. the open free volume, the microporosity, the mesoporosity and the thickness variation of thin deposited films during gas adsorption and condensation. They are all based on the coupling of the sorption of a probe gaseous molecule at room temperature and a physic...

TICOMCOM2, Formation CNRS "Techniques innovantes pour la caractérisation microstructurale de couches minces", 1-2 Avril 2008, IEM, Montpellier

2ème Journée des Polyméristes Languedociens, 5 Décembre 2008, Montpellier (France)

1ère Journée des Polyméristes Languedociens, 26 Mai 2008, Montpellier (France)

Workshop "Couches Minces et Membranes - Approches innovantes pour leur préparation, leur caractérisation et leurs applications", 3 Décembre 2008, Grenoble (France)

New design of nano porous ceramic and hybrid membranes

Workshop "Couches Minces et Membranes - Approches innovantes pour leur préparation, leur caractérisation et leurs applications", 3 Décembre 2008, Grenoble (France)