Modeling the thickness distribution of silicon oxide thin films grown by reactive magnetron sputtering

Target poisoning in reactive sputtering is one of the biggest problems in the coatings industry. In this work, we use the co-sputtering simulation reactive mode software, Co-SS Rm, to present a different solution of the compound formation both on the target and on the substrate, based on the comparison of the simulations with the thickness measurements of the films deposited at different flows of reactive gas. In these simulations, the spatial distribution of the deposited thin films is determined by analysing the angular distribution of the atoms and/ or compound ejected from the target, as well as its sputtering yield. Results indicate that the target surface poisoning suffers an evolution ejecting metallic atoms and silicon oxide until the whole racetrack area is covered by silicon oxide, but at the same time, there is a reduction in the racetrack area due to the growth of several monolayers of silicon oxide. Spectroscopic ellipsometry analysis showed the formation of SiO2 in the thin films in almost all the reactive gas flows. Simulation results were validated by thickness measurements of actual thin films and plasma optical emission spectroscopy by analysing emission transitions from the target species (Si).