Anna W. Oniszczuk¹, Afaque M. Hossain² , Wojciech Trzewiczyński¹ ,Wojciech Gajewski¹, Piotr Różański^1
1Trumpf Huettinger Sp. z o.o., Zielonka, Poland
²Trumpf Hüttinger GmbH + Co. KG, Freiburg, Germany
High Power Impulse Magnetron Sputtering (HIPIMS) combined with RF excitation on a single target provides a framework for generating stable, highly ionized plasma conditions for the deposition of materials that are prone to arcing during HIPIMS operation, such as silicon and graphite targets or highly reactive processes including aluminum sputtering in oxygen. This study investigates hybrid HIPIMS+RF operation on a single target and examines how combined excitation and pulse-protocol strategies influence plasma ionization behavior and discharge stability, with a primary focus on enhancing HIPIMS discharge stability through RF assistance.
Time-resolved and full-spectrum optical emission spectroscopic studies are used to assess plasma behavior under hybrid excitation and indicate that the addition of RF power during HIPIMS operation is consistent with improved discharge stability and a reduced probability of arc events on a silicon target. Conversely, the introduction of HIPIMS pulses during RF operation is associated with an increased contribution from ionized sputter species. The target current–voltage response shows systematic changes under hybrid excitation, and RF assistance is further associated with modifications in the attainable peak current during HIPIMS pulses, with implications for peak-power handling and process control.
A matrix of operating modes and timing schemes is explored by varying the RF-to-HIPIMS average power ratio at constant total power and evaluating synchronization strategies including simultaneous RF and HIPIMS operation, RF suppression during HIPIMS pulses, RF applied only during HIPIMS, and delayed RF excitation relative to the HIPIMS pulse. Plasma emission characteristics, reflected power behavior, arc susceptibility, and target current–voltage response are evaluated across these modes. While the present work focuses on plasma diagnostics and discharge control, it identifies relevant operating regimes and control strategies to support a subsequent materials-stage analysis in which film properties such as density, defectivity, and conformality will be assessed on test coupons and application-relevant technologies. The results support the extension of HIPIMS processing to arcing-prone materials while improving discharge stability.