There is a growing interest in producing tantalum nitride (TaN) thin films for various industrial applications. For example, in microelectronics, the development of IC technology is driven by the need to increase both performance and functionality while reducing power and cost. This goal can be achieved by several solutions among which the introduction of architecture enhancements such as 3D integration. The most challenging step is the deposition of a conformal, continuous, and adherent diffusion barrier. In this work, atomic layer deposition (ALD) of TaN thin films is explored using the combination between the thermodynamical behavior of the precursor, mass transfer in the reactor, and the operating conditions. TaN thin film deposition on very complex shape substrates, such as nanodots, TSV, silicon nanowires, and carbon nanotubes, has been evaluated.

ALD of TaN thin films is explored using the combination between the thermodynamical behavior of the precursor, mass transfer in the reactor and the operating conditions. TaN thin film has been deposited on very complex shape substrates, such as nanodots, TSV, and silicon.

Polymer fuel cell electrode growth using vapor deposition techniques is reviewed. The supports, the nanocatalyst sizes and morphologies, and the resulting electrodes are examined as a function of the vapor deposition process; sputtering, CVD, plasma-enhanced (PE)CVD, and metal-organic (MO)CVD. In each case, up-to-date fuel cell performances are highlighted. Vapor depositions are valuable techniques for designing fuel cell electrodes of various kinds with good fuel cell performances, e.g., power density and catalyst activity

The aim of the present study is to better understand the mechanisms involved during silicon deposition from silane, SiH₄, into agglomerates of sub-micrometer-size particles treated by fluidized bed (FB)CVD. Two models of silicon deposition into agglomerates assumed either stable, or in permanent formation/desegregation, are developed. In the first case, classical equations of diffusion/reaction in a porous medium are solved, whereas in the second case, the multifluid Eulerian code, MFIX, is used. By comparison with experimental energy dispersive X-ray (EDX) data, modeling results show that the limiting step is not gaseous diffusion into the agglomerates. Very high local deposition rates near the silane entrance probably explain their formation. These results allow us to propose original deposition conditions involving much lower local deposition rates, which should limit agglomeration due to CVD.

A numerical solution for the simulation of chemical vapor infiltration (CVI) of ceramic matrix composites is presented. This computational model requires a 3D representation of the preform. Gas transport and chemical reaction are simulated by a Monte Carlo random walk technique. The developed algorithm can also be used for the determination of effective transport and reaction properties in a porous medium. It is firstly validated by considering the simple case of diffusion and reaction in a flat pore. Results of infiltration of an actual fiber arrangement are described and discussed. Extension to deposition on a thin substrate with asperities is also studied

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 conditions. Polymer films of thicknesses ranging from 0.25 to 1.2 µm are obtained by both processes from the tetramethylsiloxane (TMDSO) precursor, on silicon substrates microstructured with a set of patterns (trenches, holes, and columns) with various spacings, and with vertical dimensions of 1.3 or 1.45 µm. Analysis by scanning electron microscopy (SEM) of the samples is carried out after sample cleavage. The effects of pattern size and shape, defined by the aspect ratio parameter, on the local growth rate are studied more specifically for trenches for both PECVD and RPECVD processes

The influence of the processing parameters on conformality is studied for pulsed-pressure (PP) metal-organic (MO)CVD. A statistical method to measure conformality, and a model for pulse vapor exposure are presented. Titanium dioxide (TiO₂) thin films are deposited from a liquid titanium isopropoxide (TTIP, Ti(OPr)₄) solution with no carrier gas on silicon and silicon nitride substrates with 3-D micrometer- and nanometer-scale structures. The deposited films are columnar anatase TiO₂ with thicknesses between 130 nm and 310 nm, controlled by the number of pulses. The statistical conformality varies from 0.81 to 0.93, decreased slightly with increasing deposition temperature, and is insensitive to pulse exposure.

The effect of pulsed-pressure MOCVD processing parameters on conformality was studied by TiO₂ deposition on micron-scale and nano-scale features on Si and Si₂N₃ wafer samples. A statistical measure for conformality is presented. The conformality is shown to be insensitive to processing parameters over a wide range of pulse exposure, pressure and precursor concentration for growth rates from 0.5 nm/pulse to 2.4 nm/pulse.

ZnO nanowire arrays parallel to the substrate are directly deposited by magnetron sputtering on the top of nanometric silicon line patterns prepared as a template. This method of synthesis is very simple and avoids the complicated steps of ZnO lithography. The nanoline template patterns are created by laser interference lithography combined with deep reactive ion etching. The assembly and the alignment of the nanowires after the deposition process are studied by scanning electron microscopy (SEM). The dimensions of the nanowires are regulated by those of the nanoline template patterns. The nanowires of 150 nm in width, 90 nm in height, 20 mm in length are fabricated especially for the study of their microstructure and photoluminescence effects. The microstructure is explored by X-ray diffraction (XRD) and high-resolution (HR) transmission electron microscopy (TEM). The nanowires show well-crystallized ZnO nanograins in the hexagonal würtzite structure with a (002) preferential orientation on the (100) silicon surface. The nanowires exhibit a typical photoluminescence spectrum of ZnO.

Taking the desirable attributes of CVD and aqueous plating techniques while minimizing the disadvantages of each, supercritical fluid chemical deposition (SFCD) demonstrates itself to be a promising process alternative to enable the fabrication of nanostructured devices. This paper gives information about the SFCD process for metal deposition as an alternative to CVD through various examples of inorganic deposition (films or nanostructures). In particular, the use of SFCD will be demonstrated for the surface modification of carbon nanotubes (CNTs) and their decoration with palladium nanoparticles.

In this paper we develop a model describing the ballistic transport of chemical precursor species for an atomic layer deposition (ALD) process. In the application we consider, pore geometry or surface properties of nanoporous materials are modified using ALD, taking advantage of its potential for conformal deposition in high-aspect-ratio structures. Because of the very large Knudsen number corresponding to these processes, the transport of gas-phase species inside the nanostructures takes place in a purely ballistic manner. Precursor transmission probability functions describing the fluxes between the pore surface features are developed and compared to previously published results. The transport model elements are then coupled to ALD surface-reaction models, spatially discretized, and integrated over each precursor exposure period to determine the pore spatial surface reaction extent profile. Predictions from our dynamic model are then compared to four previously published studies of ALD in nanopores to validate our simulator, and to gain further insight into the physical mechanisms at work in ALD processes. The utility of physically based models of the type we develop can be exploited to determine optimal precursor exposure levels for ALD-based nanomanufacturing operations.

Complex materials, exhibiting a cocktail of properties, are currently needed for many applications. In this context, new requirements arise in terms of materials processing, such as the synthesis of sub-micrometer objects, or the coating and functionalization of complex surfaces of powders, porous materials, or micro-patterned devices. Depending on the requirements, the aim may be to duplicate the original design of the surface, or to modify it (filling of holes etc.). Physical vapor deposition (PVD) and CVD are promising techniques for the deposition of thin films on such substrates. In order to compare the ability of various deposition techniques to coat complex surfaces, a micro-patterned silicon wafer has been developed. In the present work, aluminum thin films are deposited on this model substrate by two PVD techniques; pulsed laser deposition (PLD) and magnetron sputtering (MS), and by metal-organic (MO)CVD. Scanning electron microscopy (SEM) is performed in order to determine the microstructure and study the thickness conformity.

Physical vapor deposition (PVD) and chemical vapor deposition (CVD) are promising techniques for the deposition of thin films. In order to compare their ability to coat complex shaped surfaces, a micro-patterned silicon wafer has been developed. Aluminum thin films were deposited on this model substrate by pulsed laser deposition (PLD), magnetron sputtering (MS); and metal organic chemical vapor deposition (MOCVD). Results show that deposition by MOCVD in optimized conditions yield to conformal deposits. With MS, side and bottom thicknesses can be tailored by playing with the pattern dimensions, while PLD allows coating of a substrate, with the original pattern shape being transferred into the growing film.