In this work calcium silicide films grown by MBE method on a Si(111) substrate at a temperature of 500 °C with deposition flux ratios NCa : NSi = 3.49, 3.98, the formation of a epitaxial Ca5Si3 film with a thickness of up to 40 nm was detected, which was proven by XRD method. Reflection peaks in the region of interband transitions at 2.2, 2.75, 3.57 and 4.4 eV, a semi-metallic character of reflection at energies less than 0.5 eV, partial transmittance at 0.4−1.25 eV and a unique phonon structure with Raman shifts at 102, 110, 124, 160, 190, 220, 241, 344 and 379 cm−1 were detected for the first time in the reflection and Raman spectra of the Ca5Si3 film.