DIFFUSION PROCESSES IN METAL LAYERS OF Mo/Si MULTILAYER X-RAY MIRRORS DURING DEPOSITION

Small-angle reflectometry, X-ray diffractometry and X-ray tensometry (=0.154 nm) were used to study the structure of Mo layers in Mo/Si multilayer X-ray mirrors produced by magnetron sputtering as a function of the Ar pressure in the range of 1…4 mTorr. Two series of samples with periods of about 7 and 14 nm were produced. In all MXMs, Mo layers were crystalline (c-Mo) and Si layers were amorphous. On average, the lattice parameter a0 in the unstressed state is smaller for the 7 series samples than for the 14 nm series. It increases with Ar pressure, approaching the tabular one. On average, the lattice parameter a0 in the unstressed state for Mo layers is smaller for the 7 nm series samples than for the 14 nm series. The Si content in the c-Mo layers has been estimated. Diffusion coefficients of silicon atoms into c-Mo layers and their activation energies are determined. Diffusion mechanisms are proposed.