Ballistic and molecular dynamics simulations of aluminum deposition in micro-trenches

Two different feature scale modeling frameworks are utilized for the study of aluminum (Al) deposition profiles inside micro-trenches. The first framework, which is applied in metal-organic chemical vapor deposition (MOCVD) of Al, couples a ballistic model for the local flux calculation, a surface chemistry model, and a profile evolution algorithm. The calculated conformity of the deposited film is compared with experimental results corresponding to Al MOCVD from dimethylethylamine alane (DMEAA). The outcome of the comparison is that the effective sticking coefficient of DMEAA is in the range of 0.1 - 1. There is also a strong indication that surface reaction kinetics follows Langmuir - Hinshelwood or Eley - Rideal mechanism. The second framework, which is applied in physical vapor deposition of Al, implements 2D molecular dynamics (MD) simulations. The simulations are performed in a "miniaturized" domain of some hundreds of Angstroms and are used to explore micro-trench filling during magnetron sputtering deposition of Al on a rotated substrate. Most of the experimental results are qualitatively reproduced by the MD simulations; the rotation, aspect ratio, and kinetic energy effects are correctly described despite the completely different length scales of simulation and experiment. The sticking probability of Al is calculated 0.6 for the conditions of the experiments

Optimization of DC reactive magnetron sputtering deposition process for efficient YSZ electrolyte thin film SOFC

International audienceYttria-stabilized zirconia (YSZ, ZrO2:Y2O3) thin films were deposited by reactive DC magnetron sputtering with a high deposition rate from a metallic target of Zr/Y in an argon/oxygen atmosphere. Plasma parameters and composition analysis of the gas phase reveal that the sputtering process in the "compound" mode is reached for a 2.5 sccm oxygen flow rate. Deposition onto silicon in "metal" mode at a flow rate close to the transition, allows obtaining at very high deposition rates (> 10 µm.h-1) a compact columnar stoichiometric crystallized YSZ film. When deposited on NiO YSZ commercial anode, the obtained coatings show the same properties. In spite of the complexity of the substrate (roughness and porosity), a compact and conformed layer was formed. Annealing treatments in air or hydrogen do not significantly alter the structure of the layers. Electrochemical test at 850°C with a screen-printed LSM (LaSrMnO3) cathode exhibits a satisfying gastightness (OCV=900 mV) and a maximum power density of 350 mW.cm-2

Energy transferred to the substrate surface during reactive magnetron sputtering of aluminum in Ar/O2 atmosphere

International audienceA study of the reactive sputtering of aluminum was carried out by coupling energy flux measurements at the substrate location with conventional diagnostics of the gas phase and analyses of the deposited films. The main purpose was to get some insight into the elementary mechanisms involved at the substrate surface during the film growth in the well known metal and oxide regimes and at the transitions from one to another. Measurements were carried out in front of a 10 cmAl target at a power of 400W (i.e. 5 W/cm2) and a total pressure of 0.6 Pa. The flow rate ratio (O2/O2+Ar) was varied in the range 0 to 50 %. Different kinetics and values of energy transfer, denoting different involved mechanisms, were evidenced at metal-oxide (increasing flow rate) and oxide-metal (decreasing flow rate) transitions. The metal-oxide transition was found to be a progressive process, in agreement with optical emission spectroscopy and deposit analysis, characterized by an increase of the energy flux that could be due to the oxidation of the growing metal film. On the contrary, oxide-metal transition is abrupt, and a high energy released at the beginning that could not be attributed to a chemical reaction. The possible effect of O-ions at this step was discussed

Influence of the HiPIMS voltage on the time resolved platinum ions energy distributions

International audienceHigh Power Impulse magnetron sputtering (HiPIMS) is a common way to create a high and dense ionized metallic vapor without the use of an alternative ionizing device, like radio frequency loops. HiPIMS has been used to perform the deposition of platinum thin films in order to control their morphology. This feature known to depend on the energy of the Pt species incoming onto the substrate during the deposition has to be carefully studied. Therefore, it's necessary to study the ions energy distribution during the sputtering pulse and to follow its evolution with the HiPIMS regime. Pictures of this evolution are presented

Functionalization of, and Deposition on Complex-Shaped Surfaces: Vacuum Processes, Materials, Models, Challenges, and Methods

International audienc

Dépôts multicouches Fe/W sur substrat de Fe par pulvérisation magnétron D.C.

Le masque des tubes cathodiques est un élément déterminant pour la qualité de l image d un téléviseur. Le masque est une grille de fer (Fe) oxydée sous forme de magnétite (Fe3O4). Le bombardement électronique subi par le masque génère des gradients de température. Il s en suit une déformation du masque. L image perd alors en contraste et en brillance. L étude a porté sur la détermination, l élaboration et la caractérisation d une couche mince limitant ce gradient de température. Le matériau choisi pour cette couche protectrice est le tungstène (W) associé au Fer (Fe) sous sa forme oxyde Fe3O4. Le tungstène est un matériau réfractaire avec un haut coefficient de rétrodiffusion des électrons. De plus, Fe3O4 possède un bon coefficient d émissivité thermique. Ces deux propriétés sont essentielles pour éviter la déformation due au gradient de température. L étude a porté sur les dépôts de couches minces (système bicouche) W-Fe3O4 mais aussi alliage W-Fe sur substrat de Fe (matériau du masque). Les dépôts ont été réalisés par pulvérisation magnétron au moyen d un générateur à décharge continue (pulsée ou non) avec ou sans l assistance d un plasma auxiliaire radiofréquece créé par une antenne interne. Pour tenter d obtenir une couche mince de Fe3O4, nous avons étudié les oxydations ex-situ après dépôts ainsi qu in-situ pendant ou après dépôts (en les comparant entre elles). Les caractérisations ont concerné l étude de la structure (microscopie électronique, diffraction des rayons X), l adhérence (test scotch et diffraction X sous traction), la composition (spectroscopie de Rétrodiffusion Rutherford et Analyse par Réaction Nucléaire).ORLEANS-BU Sciences (452342104) / SudocSudocFranceF

Plasma sputter deposition of Aluminum onto micropatterned silicon substrates: Experiments and molecular dynamics simulations

International audienc

Theory and molecular simulations of plasma sputtering, transport and deposition processes

The present review provides an overview of the basic theory of sputtering with recent models, focusing in particular on sputtered atom energy distribution functions. Molecular models such as Monte-Carlo, kinetic Monte-Carlo, and classical Molecular Dynamics simulations are presented due to their ability to describe the various processes involved in sputter deposition at the atomic and molecular scale as required. The sputter plasma, the sputtering mechanisms, the transport of sputtered material and its deposition leading to thin film growth can be addressed using these molecular simulations. In all cases, the underlying methodologies and some selected mechanisms are highlighted