Y. Shen, ¹ M. Wiosna, ² Wojciech Gajewski, ² Mohammad Afaque Hossain^1
1TRUMPF Hüttinger GmbH + Co. KG, Freiburg im Breisgau, Germany
²TRUMPF Huettinger Sp. z o.o., Zielonka, Poland
Achieving high deposition rates and plasma stability remains a key challenge in reactive magnetron sputtering for large-area optical coatings. This study introduces an advanced Bipolar Bidirectional Pulsing (BDP) concept as a next-generation powering mode designed to enhance both deposition efficiency and plasma control. Comparative experiments between standard bipolar and BDP operation were conducted under identical/close-similar process conditions for SiO_₂ deposition.
The BDP mode, characterized by a sequence of symmetric pulse packages with controlled off-times, demonstrated up to 26% higher deposition rates than standard bipolar pulsing while maintaining comparable optical and mechanical film properties. Plasma diagnostics revealed lower ion current density and floating potential, resulting in reduced heat load, improved charge balance, and enhanced plasma stability — key advantages for minimizing arcing and droplet defects in conductive–insulating–conductive layer stacks. Additionally, preliminary observations indicated lower particle density and smoother film morphology.
These findings confirm that Bipolar BDP technology offers a robust, energy-efficient, and industrially scalable powering strategy for optical coating applications, enabling higher throughput and improved plasma stability in advanced thin-film deposition systems.