  We propose a way of formation of thin bilayer Pt$_3$Si/Pt$_2$Si films at room
temperature on poly-Si substrates by Pt magnetron sputtering and wet etching,
obtain such film, investigate its structure and phase composition and estimate
the thickness of its layers. We verify by direct x-ray
photoelectron-spectroscopic measurements our previous observation of the
Pt$_2$Si layer formaton between Pt and poly-Si films as a result of Pt
magnetron sputtering at room temperature. This layer likely appears due to high
enough temperature of Pt ions in the magnetron plasma sufficient for chemical
reaction of the silicide film formation on the Si surface. The Pt$_3$Si layer
likely forms from the Pt--Pt$_3$Si layer (Pt$_{95}$Si$_5$), which arises under
Pt film during the magnetron sputtering, as a result of Pt removal by wet
etching.
