La thèse s’inscrit dans la problématique du dépôt de couches minces en procédés de pulvérisation réactive cathodique magnétron continu basse puissance (R-DC) et pulsé haute puissance (R-HiPIMS). Le mode réactif consiste à ajouter, dans l’argon, un gaz réactif tels que l’oxygène ou l’azote. Les oxydes et les nitrures ont de très nombreuses applications industrielles. Néanmoins, les exigences des nouvelles applications nécessitent de mieux comprendre, contrôler et maîtriser les processus fondamentaux gouvernant le transport de la matière pour optimiser ces procédés plasmas. L’objectif principal de cette thèse est d’étudier le transport des atomes pulvérisés de titane (Ti) en mélange Ar/N2 et d’établir des corrélations avec les propriétés des dépôts de type TiN. La fluorescence induite par diode laser (résolue en temps dans le cas du procédé HiPIMS) a été développée pour mesurer les fonctions de distribution en vitesse des atomes neutres Ti à l’état fondamental en fonction de la pression, de la distance par rapport à la cible et du mélange gazeux. Le degré de liberté supplémentaire qu'offre la dimension temporelle du plasma HiPIMS a permis de caractériser leur cinétique de transport en ayant la possibilité de séparer les temps caractéristiques des différents processus, et de mettre en évidence trois populations d’atomes (énergétique, quasi-thermalisée et thermalisée). Les fonctions de distribution en énergie des ions Ti+ ont été mesurées par spectrométrie de masse et des hypothèses sont proposées pour pouvoir expliquer les quatre populations identifiées. Enfin, les couches minces déposées ont été analysées par MEB, DRX et microsonde de Castaing. / The growth of thin layers in reactive-direct current magnetron sputtering (R-DC) and reactive-high power impulse magnetron sputtering (R-HiPIMS) processes is the general framework of this PhD. Reactive processes consist in the addition, in argon gas, of a reactive gas such as oxygen or nitrogen, and allow the deposition of oxides and nitrides which have many industrial applications. Nevertheless, the high level of expectations regarding new applications requires a better understanding, controlling, mastering of basic processes governing atoms transport in the view of process optimization. The main goal of this PhD is to study the transport of sputtered titanium atoms (Ti) in Ar/N2 gas mixture and to establish correlations with TiN film properties. Tunable diode laser induced fluorescence technique (time resolved in the case of HiPIMS process) has been developed in order to measure velocity distribution functions of neutral Ti atoms at the ground state, function of the pressure, the distance from the target and the gas mixture. In HiPIMS, the additional degree of freedom, given by time dimension, allowed to characterize their kinetic of transport while at the same time providing the possibility to separate characteristic time scales of different processes. Three atoms populations have been highlighted (energetic, quasi-thermalized and thermalized ones). Energy distribution functions of Ti+ ions have been measured using mass spectrometry and four populations have been observed and explained. Finally, deposited thin films have been analyzed by means of SEM, XRD and electron microprobe methods.

Spatially-resolved measurements of flame temperature have been demonstrated with diode lasers for the first time. The technique is based on the use of blue diode lasers to perform laser-induced fluorescence on indium atoms seeded to the flame. Temperature measurements have been carried out in laminar flames both by the two-line atomic fluorescence technique, and also by a novel line-shape thermometry method that requires the use of only a single diode laser. The first part of this work involved the development of blue extended cavity diode lasers with favourable tuning properties. Two custom-designed extended cavity diode lasers (ECDL) have been built, emitting at wavelengths of around 410 nm and 451 nm respectively. These devices are capable of mode-hop free tuning over ranges greater than 90 GHz. The performance of these devices exceeds that of commercially available systems and a patent application has been filed. High resolution fluorescence spectroscopy has been performed on both the 52P1/2→62S1/2 and 52P3/2→62S1/2 transitions of indium atoms seeded at trace quantities into atmospheric pressure flames. In both cases, the spectra obtained show excellent agreement with a theoretical fit based on the individual hyperfine components of the transition. The two ECDLs have been used to build a sensor for the measurement of temperature in combustion systems. It is much simpler, more compact, less expensive, and more versatile than any previously existing device. The two lasers were used sequentially to probe indium atoms seeded to the flame. The ratio of the resulting fluorescence signals is related to the relative populations in the two sub-levels of the spin-orbit split ground state of indium, and thus to the temperature. Temperature measurements have been successfully performed in a laminar flame and the data thus obtained do not need to be corrected by any ‘calibration constant’. This novel thermometry technique offers a robust alternative to traditional methods involving bulky high power lasers. A further development has been made by demonstrating a fluorescence line-shape thermometry technique requiring only a single diode laser excitation source. Progress has been made towards the goal of rapid temperature measurements appropriate to the study of turbulent flames. This involved the development of a simple technique for actively locking the wavelength of the blue diode laser to a resonance line of the tellurium molecule. A high-speed thermometry system would work by rapidly switching between the two locked laser beams using an optical modulator.

La pulvérisation cathodique magnétron est un procédé plasma très répandu dans l'industrie pour le dépôt de couches minces. Néanmoins, les exigences des nouvelles applications nécessitent de mieux comprendre, contrôler et maîtriser les processus fondamentaux gouvernant le transport de la matière pour optimiser le procédé. Ce travail de thèse porte sur l'étude du transport des atomes pulvérisés de tungstène (W) en décharge magnétron continu (DC direct current) et pulsée haute puissance (HiPIMS_high power impulse magnétron sputtering). La fluorescence induite par diode laser (TD-LIF) a été mise au point afin de mesurer les fonctions de distribution en vitesse des atomes W pulvérisés. Les mesures ont été calibrées par absorption laser et validées en corrélant avec les vitesses de dépôt. En procédé DC, l'étude de l’influence des paramètres de la décharge (puissance, tension, mélange gazeux Ar/He, distance par rapport à la cible, etc.) a mis en évidence l'évolution spatiale des régimes de transport balistique (atomes énergétiques), diffusif (atomes thermalisés), et mixte (balistique+diffusif). Pour l'étude du procédé HiPIMS, le plasma pulsé a nécessité de développer la TD-LIF résolue en temps (TR-TDLIF). Le degré de liberté supplémentaire qu'offre la dimension temporelle du plasma HiPIMS a permis de mieux comprendre le transport mixte qui représente le cas le plus compliqué. En effet, cela a permis de mesurer la cinétique du transport des atomes pulvérisés en ayant la possibilité de séparer les temps caractéristiques des différents processus / Magnetron sputter deposition is an established and widely used method for the growth of thin films. Nevertheless, the high level of expectations regarding new applications require a better understanding, controlling, mastering of basic processes governing atoms transport in the view of process optimization. This work consist in the study of transport of sputtered W atoms in direct current and high power impulse magnetron discharges (DC and HiPIMS). A tunable diode laser induced fluorescence technique (TD-LIF) has been developed, in order to measure W sputtered atom velocity distribution function. Measurements were calibrated using laser absorption and were corroborated by deposition rate. In DC, the study of the influence of discharge parameters (power, voltage, Ar/He gas mixture, and distance from target, etc.) highlighted spatial evolution of different regimes of transport: ballistic (energetic atoms), diffusive (thermalized atoms), and mixed (ballistic + diffusive). In HiPIMS, pulsed plasma required to develop a time resolved TD-LIF technique (TR-TDLIF). The additional degree of freedom, given by time dimension allowed for a better understanding of mixed transport which represents the most complicated situation. This technique allowed to measure the kinetic of sputtered W atoms while at the same time providing the possibility to separate characteristic time scales of different processes