Enhancing Surface Properties of HMDSO/O ₂ Release Coatings Using Dual Frequency Discharge on Electrically Floating Objects

Dual‑frequency excitation offers a promising approach to control ion energy in capacitively coupled plasmas, but its effect on coatings deposited on electrically floating substrates remains poorly understood. In this study, HMDSO/O 2 release coatings were deposited in a low‑pressure PECVD reactor using combined 13.56 MHz and 400 kHz excitation. A floating setup mimicking roll‑to‑roll geometries was investigated at varying distances from the powered electrode. While low‑frequency power significantly increased the DC self‑bias and Young's modulus on the powered electrode, coatings on the floating substrate exhibited a moderate stiffness increase (up to ~80%) with nearly unchanged mass deposition rate and surface free energy. These results demonstrate that dual‑frequency operation enhances mechanical robustness while preserving low‑adhesion properties, even on electrically floating substrates.