Josja Van Bever from Belgium researches the double hysteresis behavior of reactive sputtering

Josja Van Bever is a third-year PhD student at Ghent University in Belgium. He works at the Department of Solid State Sciences in the research group DRAFT (Dedicated Research on Advanced Films and Targets). He studied Physics and Astronomy in his master’s program. The topic of his PhD research is the fundamental principles of processes occurring during a magnetron sputtering deposition process. He came to the Department of Plasma Physics and Technology and CEPLANT for two weeks to conduct new experiments that could contribute to his research back at home.

Josja Van Bever studies magnetron sputtering both theoretically through modeling and experiments. Reactive magnetron sputtering is a hard-to-control process. Depending on the set point conditions, one can find the process at several different operating conditions. The properties of the final product, a thin film, are set by these working conditions. Therefore, one can have different resulting films for the same process parameters. Josja uses the RSD model developed by the team at Ghent to study these metastable states. So far, they found that the target history during the sputtering process is a cause for reported double hysteresis of the reactive sputtering.

Why did you choose to come to Brno and our university?

I met Prof. Petr Vašina at the RSD conference. I presented my research on the double hysteresis behavior of reactive magnetron sputtering. Prof. Vašina approached me to ask whether I could measure the same observed behavior for the Tantalum target. From there, we had several online meetings discussing different Ta compositions in Alumina aiming at an alternative approach to measure the double hysteresis. We need good control of the system to observe and measure the double hysteresis behavior of reactive magnetron sputtering. The FlexiLAB deposition device at the DPPT and CEPLANT, here at Brno, offers some alternative diagnostics. It is also good to start further cooperation and improve networking.

Back in Ghent, we have self-made reactors. It is good to compare it to the industrial device. Also, sufficient data is needed for the process control. It is also good for comparing devices, processes, and measurements here and back in Ghent. Here in Brno, prof. Vašina’s group also has a mixed tantalum/aluminum target composition available.

What is the most exciting thing about your research?

Interestingly, it is possible to compute and model something you can observe in an actual experiment. I like the fact that I can understand the process by modeling it and then compare it to experiments. I am predicting something, and I have direct feedback from the experiment. The experiment challenges me to add corrections to our theoretical understanding.

Why did you study physics and astronomy?

It is simple. I find it interesting. When I was younger, I wanted to become a painting artist, then an engineer, then an architect. At my secondary school, I received a prize for my project in physics/mathematics, and I read the book Trespassing on Einstein’s Lawn. From there, I really wanted to understand things and have an intuitive understanding of quantum physics. So, I went and studied theoretical physics. After that, I concluded that you need experimental comparison to really understand theory.

What is the most challenging during your stay with us in Brno?

Definitively, the language. Then, the currency. The last would be the operating software of the FlexiLAB device. :)

How long are you going to stay?

I plan my stay for two weeks. The extended stay will not be helpful if the experiments do not work. If it does work, I will analyze the data and model, and in the future, I could schedule another visit. Also, measurements at the another device Alcatel here in Brno labs. The Alcatel device is interesting because it uses bigger targets and offers a fast feedback control with the Speedflow device.

Thank you for answering the questions and we wish you the best outcomes in your life and work.