Investigation of the structure and electrical properties of nanocomposite films W$_x$Si$_{1-x}$

An experimental investigation of the structure and phase composition by X-ray, Raman, and ultrasoft X-ray emission spectroscopy, as well as the study of the electrical properties of W$_x$Si$_{1-x}$ films used as sensitive elements of superconducting single-photon detectors (SNSPD), depending on the thickness in the range from 7 to 80 nm, was carried out, according to the results of which it was found that the W$_3$Si phase is presumably formed in films 20 and 40 nm thick with a resistivity of 8.4 $\cdot$ 10$^{-5}$ and 6.0 $\cdot$ 10$^{-5}$ $\Omega$ $\cdot$ cm, respectively, containing the WSi$_2$, W$_5$Si$_3$, and SiO$_2$ phases, as well as WO$_x$ and a small share of $\beta$-W. Films with a thickness of 7 nm have the highest resistivity of 18.0 $\cdot$10$^{-5}$ $\Omega$ $\cdot$ cm and contain nanocrystals, WSi$_2$, SiO$_2$, as well as $\beta$-W, and an amorphous silicon phase. Films with a thickness of 80 nm (the resistivity is also 18.0 $\cdot$ 10$^{-5}$ $\Omega$ $\cdot$ cm) predominantly contain WSi$_2$, as well as W$_5$Si$_3$ and SiO$_2$, and, presumably, the W$_3$Si phase.