Formation of structured silica layers from Dodecaphenyl POSS thin films via microwave-induced oxygen plasma treatment

The study investigated the effect of microwave-induced oxygen plasma on Dodecaphenyl-POSS (Ph12T12) thin films that were obtained by Physical Vapor Deposition (PVD) in an Ultra-High Vacuum (UHV) system. Due to its ability to self-assemble and its relatively low cost, Ph12T12 is a promising material as a precursor for the fabrication of silica thin films. The study found that the treatment of the Ph12T12 thin film with oxygen plasma results in the formation of a new material with a cage-like structure preserved. The thin films were examined using X-ray Reflectivity (XRR), Raman spectroscopy, and Atomic Force Microscopy (AFM). The results showed significant changes in the microstructure, chemical composition, and topography of the annealed POSS films. Thermal and plasma treatment improved the thermal resistance of the surface layer, increasing the evaporation temperature by over 80 °C. XRR modeling of the films' spectra enabled the determination of the composition of each interphase. Additionally, Bragg reflections (00l) remained visible on the spectra after annealing, indicating the presence of a preserved POSS cage-like structure.