Modification of wetting and mechanical traits via rapid annealing under varying temperatures for β-FeSi2

Abstract

The examination on β-FeSi₂ thin films prepared via facing-target sputtering onto Si(111), subjected to rapid thermal annealing under varying temperatures of 200–800 °C, revealed numerous changes in the film’s physical traits. The energy-dispersive X-ray spectroscope findings corroborate the anticipated atomic composition, displaying strong Si and small Fe peaks, including C and Al impurities. The Fe/Si proportions barely changed after rapid annealing. Under 200 °C and 400 °C, the X-ray diffractometer spectra indicated that orientation (202/220) and (404/440) of β-FeSi₂ were improved by rapid annealing, while surface morphology also revealed gradual enhancement in grain structure and roughness. Temperatures of over 600 °C induced recrystallization of the films, resulting in the reduced orientation peak’s intensities, grain compression, and coarsening. These changes caused the air gap to collapse, turning the film’s surface hydrophilic with contact angles of 86.15° at 600 °C and 63.00° at 800 °C. In contrast, the films retained hydrophobicity with contact angles of 93.40° at 200 °C and 91.20° at 400 °C compared to the as-prepared films of 96.75°. The hardness and Young’s modulus improved with rising temperature to 15.2 GPa and 225.8 GPa at maximum. This has ramifications for their prospective use in self-cleaning and hard-coating applications.