Structural and mid-infrared optical properties of sputtered silicon films on silicon and silicon carbide substrates

This Letter presents an investigation into the mid-infrared (mid-IR) optical properties of sputter-deposited silicon films, highlighting the impact of deposition temperature and post- deposition annealing. We explore the nuanced effects these factors have on the characteristics of silicon films deposited on various substrates, including monocrystalline silicon and silicon carbide (SiC), by employing transmission electron microscopy (TEM), grazing incidence x-ray diffraction (GIXRD), and ellipsometry. Our findings reveal that sputtering temperature and annealing treatment significantly influence the optical and structural properties of the silicon films, with high-temperature sputtering leading to the formation of polycrystalline structures on top of amorphous layers deposited on the SiC substrate. Additionally, this study presents the mid-IR optical properties of films deposited on SiC substrates at high temperatures. This research fills a gap in the existing literature regarding the mid-IR properties of sputtered silicon films and offers valuable insights for applications in silicon photonics, photovoltaics, solar cells, and mid-IR light sources, thus contributing to the advancement of technologies in optics and materials science.