March 16th, 2015
Highly precise and stable surface coatings are essential for many applications, whether for eyeglasses, or for optics for lasers or telescopes. The project PluTO created a basic understanding of plasma-based coatings. The aim of the project PluTO+ is now to transfer these to industrial applications. For this, the Laser Zentrum Hannover e.V. (LZH) is working on controlling ion beam sputtering (IBS).
Up to now, IBS processes, in comparison to magnetron processes for example, could only be guided by using set parameters, but without online control. Fundamental knowledge of the influence of plasma parameters was missing. For this reason, the Process Development Group of the LZH investigated how exactly IBS coating processes work, within the framework of the joint project PluTO (Plasma and optical technologies). For example, they were able to quantify the ions of sputtered materials separately from the background plasma. Furthermore, they could analyze in detail the reactive processes on the target surface. With this knowledge, they were able to develop new strategies to decisively improve the quality, reproducibility and exploitation of IBS processes.
IBS process with two ion sources in use. Photo: LZH
Simulation of the process beforehand
Additionally, the scientists developed a new, versatile tool for describing layer condensation. This tool can be used to simulate processes on an atomic level, so that in the future it is possible to adapt the parameters to the demands of deposition processes, for example for the stoichiometry, thickness or roughness of the layers.
In the recently started follow-up project PluTO+, information from the project PluTO are to be transferred into industry. For this, the LZH has developed control sequences for the IBS process. In combination with innovative plasma diagnostics, it would be possible to follow the course of a process online, to make predictions, and accordingly intervene in these processes. This would make the coating processes more precise, more stable and faster and thus less expensive.
IBS coating unit with process analysis. Photo: LZH
In the collaborative project PluTO, five research organizations in the fields of plasma technology and optical thin-film coating technology have worked on gaining basic knowledge on plasma supported coating processes. The PluTO+ network consists of four research institutes and eight industrial partners under leadership of the Bühler Alzenau GmbH. Both PluTO and PluTO+ have been funded by the German Federal Ministry of Education and Research.
