Home – Home – Jornals – Avtometriya 2023 number 6

Under ultra-high vacuum conditions, epitaxial and polycrystalline films of iron (Fe), chromium (Cr), and calcium (Ca) silicides of various thicknesses (from 3.2 nm to 380 nm) are grown on silicon and sapphire substrates by three methods (solid phase epitaxy (SPE), reactive epitaxy (RE), and molecular beam epitaxy (MBE)). The crystal structure and matching with the silicon lattice are determined for them using the X-ray diffraction (XRD) method. A comparative analysis of Raman spectra (RS) and far-IR spectroscopy spectra shows that films of semiconductor silicides have the maximum intensity of Raman peaks, and the detected shifts in their positions are caused by distortions in the silicide lattices. It has been established that the intensity of Raman peaks in films of iron and chromium monosilicides at a fixed laser excitation wavelength (λ = 628.3 nm) and a power of 3.4 mW decreases with decreasing film thickness, which leads to their complete disappearance at a thickness below 10 nm. Chromium trisilicide films are grown on single-crystal sapphire, which makes it possible for the first time to detect Raman-active phonons at 214.3 cm^-1 and 273.1 cm^-1 at λ = 488 nm and a power of 0.42 mW. The studied films of transition metal monosilicides are of significant interest from the viewpoint of the prospects for their use as materials for thermoelectronics and spintronics, and systematic information on Raman-active and IR-active phonons will allow rapid determination the phase type formed immediately after film growth.