Molecular Dynamics simulations of magnetron (reactive) sputtering and deposition

Pascal Brault (1)

1 GREMI - Groupe de recherches sur l'énergétique des milieux ionisés

Magnetron (reactive) sputtering is a widely used technique/technology both in research and in industry. Nevertheless, this fairly simple technology is continuously being improved. A first interest of magnetron sputtering is to build coatings with improved or complementary properties compared to the pristine bulk materials. Essentially, thin film properties are related on composition and microstructures, which in turn are depending on the deposition conditions and thus from sputtering plasma properties. A second specific property of plasma sputtering and thus more specifically magnetron (reactive) sputtering is it acts as an atom source, able to interact with an inert and/or reactive buffer gas, which is contributing to the plasma ignition and properties. Such a source is thus providing a sputtered vapor (more or less directed) with a well defined composition, kinetic energy and angle distributions. Such “initial conditions” are determining the building of thin film, for which a special initial stage is the growth of supported clusters which may have interests in themselves. Studying plasma sputter growth of supported clusters and thin films remains a challenging task for understanding current properties (film morphology, use properties) and predicting new properties. Due to the atomic nature of this atom/molecule source and the resulting deposition process, an insight of the sputtering and deposition processes at the molecular scale is thus of paramount importance. Molecular Dynamics is a simulation technique that is well suited for describing materials at the atomic scale and thus is well suited for predicting sputtered matter properties and subsequent grown clusters and thin film compositions and morphologies. So, numerous approaches have been proposed for describing plasma-surface phenomena. Such a focus on plasma sputtering and deposition using MD is intended for illustrating the power of MD and the capability of predicting morphology, structure and composition in agreement with experimental results. This review will thus present how to handle MD simulation in the context of plasma sputtering mechanism and deposition, especially with emphasis on initial conditions. Effects of depositing atom kinetic energies and atomic composition will be studied in order to correlate with morphologies and atomic structure. Classical molecular dynamics (MD) is a method intended to numerically solve the Newton equations of motion for a given system of particles, for which the interactions are governed by a model describing the forces between these particles. An advantage of molecular dynamics simulations is that systems can be studied with an atomic resolution at short time- and length-scales, down to femtoseconds and angstroms up to nanoseconds and sometimes to microseconds (Hansen, 2000). A very striking advantage in MD simulations is no assumption is made about the mechanisms operating in the system. Moreover, based on the experimental conditions, the result of computational simulation may lead to the discovery of new physical mechanisms. Besides, the thermodynamics information of the system describing the driving force for atomic interactions can also be obtained from MD simulation which expresses the energetic relationships between its various possible states

Domaines: Plasmas; Matériaux

Pascal Brault. Molecular Dynamics simulations of magnetron (reactive) sputtering and deposition. 13th Reactive Sputerring Deposition Conference - RSD2014, Nov 2014, Gent, Belgium. ⟨hal-01120869⟩