Papers by Francis Baillet
Journal of Laser Applications, 2015
ABSTRACT This paper investigates the laser micromachining of SiC-4H wafers with an ultraviolet (3... more ABSTRACT This paper investigates the laser micromachining of SiC-4H wafers with an ultraviolet (355 nm) nanosecond source. The design of experiment methodology was used to study the effect of pulse energy, number of passes, defocus, and scanning speed on scribing depth and was modeled with Design Expert® software. Pulse energy and scanning speed were found to have a significant effect on scribe depth (by a factor of 10 compared to defocus), while the effect of the number of passes varied with pulse energy and scanning speed. The model predicted a narrow set of processing parameters to scribe half of the wafer thickness (180/360 μm). A more fundamental study was also conducted in order to validate literature observations on the ablation mechanism. A brief comparison between conventional blade dicing and the laser scribe-break method was performed on a 3 in. diameter wafer. It was discovered that a possible gain of gross die (number of usable chips per wafer) of 7% could be achieved which could provide a useful economic benefit.
The Canadian Journal of Chemical Engineering, 1998
Abstract Un réacteur bioélectrochimique à cathode volumique de grains de carbone régénère les ion... more Abstract Un réacteur bioélectrochimique à cathode volumique de grains de carbone régénère les ions ferreux, substrat de la bactérie acidophile autotrophe Thiobacillusferrooxidans DSM 583. L'implantation d'un régulateur, non linéaire linéarisant ...
Journal of the European Ceramic Society, 2012
The heat treatment of SiC powders, SiC-2 mol% SiO 2 powder mixtures, and bimodal SiC powder mixtu... more The heat treatment of SiC powders, SiC-2 mol% SiO 2 powder mixtures, and bimodal SiC powder mixtures has been studied with a quadrupole mass spectrometer linked by capillary tube to a special heat treatment reactor. Silica release was monitored on the CO(g) vaporized flow and the samples were analyzed by Raman spectroscopy and Scanning Electron Microscopy after the experiments. The present study showed that silica release by vaporization-first step in heating processes-is needed before any SiC growth process could start. The second step involving active SiC oxidation conditions by the remaining oxygen was conducive to the growth of "neck-like" connections between SiC grains and growth process was observed in the 1273-1600 K range. When the CO(g) release decreased as a result of higher temperatures or longer treatment times, carbon precipitation at the SiC surface was observed as the third step in the mass loss process.
hASC phenotype, comparison of ALP staining and ALP enzymatic activity for the rapid measurement o... more hASC phenotype, comparison of ALP staining and ALP enzymatic activity for the rapid measurement of the ALP expression and comparison of different ALP staining time points. (DOCX 2716 kb)
Substrate heater design investigation for uniform temperature in a cold-wall low pressure reactor... more Substrate heater design investigation for uniform temperature in a cold-wall low pressure reactor p. 13 Elaboration on the automatic modelling system for reaction mechanism using a novel calculation method p. 21 Toward a systematic methodology for modelling vapor deposition processes p. 29 Expanding thermal plasma CVD : experimental studies of the plasma-surface interaction p. 36 RTLPCVD modelling : steady-state simulations p. 49 The effect of ozone on the growth rate of tin oxide from monobutyltin trichloride p. 57 A critical evaluation of surface reaction models based on reactive sticking coefficients p. 65 Multiple experimental investigation for understanding CVD mechanism : example of laminar pyrocarbon deposition p. 73 Gas phase association reactions in 13-15 CVD : annoying obstacle or rewarding advantage? p. 87 A multiscale study of the MOCVD of GaN p. 95 The decomposition mechanism of a gallium azide single molecule precursor derived from accurate theoretical calculations p. ...
Le travail presente dans ce memoire traite de l'utilisation de la bacterie acidophile thiobac... more Le travail presente dans ce memoire traite de l'utilisation de la bacterie acidophile thiobacillus ferrooxidans pour la biosoption des metaux toxiques contenus dans les effluents industriels et la mise au point d'un procede de traitement d'effluent utilisant cette bacterie. Les proprietes de resistance et de biosorption de t. Ferrooxidans vis-a-vis du cadmium et du chrome sont etudiees. Les resultats montrent que la souche bacterienne utilisee (dsm 583) resiste et s'adapte a de fortes concentrations en metaux et que d'importantes quantites de metal sont fixees (respectivement 0. 2 g de cd#2#+ et 0. 5 g de cr#6#+ par gramme de biomasse seche). Des cliches realises par microscopie electronique a transmission permettent d'observer des precipites a la surface des bacteries indiquant un mecanisme de bioprecipitation des metaux. Cette hypothese est confirmee par des tests d'elution des metaux fixes et la mise au point d'un modele empirique, par la methodolo...
L'invention concerne un dispositif (10) de formation a l'etat monocristallin d'un cor... more L'invention concerne un dispositif (10) de formation a l'etat monocristallin d'un corps compose a evaporation non congruente, susceptible d'exister sous forme monocristalline ou polycristalline, comportant une premiere enceinte (20) contenant un substrat (42) au niveau duquel est formee une source polycristalline dudit corps et un germe (46) monocristallin dudit corps ; une seconde enceinte (14), ledit substrat etant dispose entre les deux enceinte ; des moyens d'apport (36) de precurseurs gazeux dudit corps dans la seconde enceinte propres a provoquer le depot dudit corps sous forme polycristalline sur le substrat ; et des moyens de chauffage (26) pour maintenir le substrat a une temperature superieure a la temperature du germe de facon a provoquer la sublimation de la source polycristalline et le depot sur le germe dudit corps sous forme monocristalline.
The invention concerns a method for forming catalytic sites at the surface of a support, which co... more The invention concerns a method for forming catalytic sites at the surface of a support, which consists in: depositing on said surface a liquid film (3) containing elements (4) of a living matter, capable of moving when subjected to an electric and/or magnetic field and designed to form catalytic traces or alterations at the surface of the substrate; applying an electric and/or magnetic field to said film such that, under the effect of the field, at least some of said living matter elements move and assemble on zones of the substrate surface; and eliminating the liquid film and the living matter at the substrate surface while allowing the traces left by said living element at the substrate surface to subsist so as to constitute said catalytic sites at the locations of said traces.
ECS Meeting Abstracts
not Available.
Stem Cell Research & Therapy
Background: Human adipose-derived stromal cells (hASCs) have been gaining increasing popularity i... more Background: Human adipose-derived stromal cells (hASCs) have been gaining increasing popularity in regenerative medicine thanks to their multipotency, ease of collection, and efficient culture. Similarly to other stromal cells, their function is particularly sensitive to the culture conditions, including the composition of the culture medium. Given the large number of parameters that can play a role in their specification, the rapid assessment would be beneficial to allow the optimization of their culture parameters. Method: Herein we used the design of experiments (DOE) method to rapidly screen the influence and relevance of several culture parameters on the osteogenic differentiation of hASCs. Specifically, seven cell culture parameters were selected for this study based on a literature review. These parameters included the source of hASCs (the different providers having different methods for processing the cells prior to their external use), the source of serum (fetal bovine serum vs. human platelet lysate), and several soluble osteoinductive factors, including dexamethasone and a potent growth factor, the bone morphogenetic protein-9 (BMP-9). The expression of alkaline phosphatase was quantified as a readout for the osteogenic differentiation of hASCs. Results: The DOE analysis enabled to classify the seven studied parameters according to their relative influence on the osteogenic differentiation of hASCs. Notably, the source of serum was found to have a major effect on the osteogenic differentiation of hASCs as well as their origin (different providers) and the presence of L-ascorbate-2phosphate and BMP-9. Conclusion: The DOE-based screening is a valuable approach for the classification of the impact of several cell culture parameters on the osteogenic differentiation of hASCs.
Coatings
This study aims to present the interest of using a design of experiments (DOE) approach for asses... more This study aims to present the interest of using a design of experiments (DOE) approach for assessing, understanding and improving the hydride vapor phase epitaxy (HVPE) process, a particular class of chemical vapor deposition (CVD) process. The case of the HVPE epitaxial growth of AlN on (0001) sapphire will illustrate this approach. The study proposes the assessment of the influence of 15 process parameters on the quality or desired properties of the grown layers measured by 9 responses. The general method used is a screening design with the Hadamard matrix of order 16. For the first time in the growth of AlN by CVD, a reliable estimation of errors is proposed on the measured responses. This study demonstrates that uncontrolled release of condensed species from the cold wall is the main drawback of this process, explaining many properties of the grown layers that could be mistakenly attributed to other phenomena without the use of a DOE. It appears also that the size of nucleation islands, and its corollary, the stress state of the layer at room temperature, are key points. They are strongly correlated to the crystal quality. Due to the intrinsic limitations of the screening design, the complete optimization of responses cannot be proposed but general guidelines for hydride (or halogen) vapor phase epitaxy (HVPE) experimentations, in particular with cold wall apparatus, are given.
Materials Science Forum, 2007
Raman spectroscopy and photoemission microscopy were coupled as two complementary non-destructive... more Raman spectroscopy and photoemission microscopy were coupled as two complementary non-destructive optical techniques in order to study biased 4H-SiC pin diodes. These two characterization tools have been largely used for the study of semiconductors but the combination of these two techniques has hardly been reported so far. Some structural defects inducing the same electrical damage could be discriminated and identified. Temperature could be measured in operating devices and the influence of the diode operating mode on the Raman signal could be evidenced.
Materials Science Forum, 2003
In a new reactor concept, with SiC feeding by CVD deposition and sublimation in a same crucible, ... more In a new reactor concept, with SiC feeding by CVD deposition and sublimation in a same crucible, the chemical vapor deposition on graphite plates and through a graphite foam was investigated. Presented results show the evolution of SiC deposition versus temperature on graphite plates and in the graphite foams used to separate the sublimation area from the deposition area. SiC obtained from tetramethylsilane decomposition is characterized by XRay diffraction and its distribution is investigated by mass measurements and microscopy.
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Papers by Francis Baillet