Influence of Fluorine on Structural and Electrical Properties of VO2 Thin Films Deposited by Magnetron Sputtering

Abstract

This study investigates whether fluorine-based thermal gel used during electrical measurements of vanadium oxide (VO2) films influences the structural, morphological, or compositional integrity of the films. High-quality VO2 films with a resistance ratio change of about 10(4) for metal-insulator transition were deposited by magnetron sputtering. During electrical characterization, VO2 film was heated from room temperature to similar to 370 K with a fluorine-based thermal gel usage to achieve better heat contact between the film and substrate holder. Structural and chemical properties were assessed through XRD, Raman, XPS, SEM, and energy dispersive spectroscopy imaging. XRD revealed diffraction peaks consistent with monoclinic VO2 confirming that the crystal lattice remains the same although fluorine based thermal gel was used. Raman spectra exhibited vibrational modes indicating that the phonon structure of VO2 was preserved despite fluorine gel usage. XPS results showed only a minor F 1s signal (2.8%) limited only to the film surface. SEM and EDS analyses further confirmed that surface morphology and elemental composition remained belonging to VO2 film. These findings demonstrate that the usage of fluorine-based thermal gel results in only a minimal surface interaction, thereby preserving intrinsic material properties of VO2 and supporting a potential usage for future device fabrication applications.