Niobium, indium, and tin heterodiffusion during formation of two-layer systems on silicon single crystals

Abstract

Rutherford back-scattering, powder X-ray diffraction, and mathematical simulation were used to study heterodiffusion of components during formation of two-layer metallic thin-film (∼300 nm) Nb, In-Nb, and Sn-Nb systems on silicon single crystals. In terms of the Darken’s model for description of the Kirkendall effect, it follows that, during magnetron sputtering, niobium penetrates into silicon with an individual chemical diffusion coefficient of DNb→Si =1 × 10−15 cm2/s. Sputtering of a second metal (Sn or In) onto a niobium film stimulates the mass transfer of components through the Nb/Si interface and increases DNb→Si by a factor of 3 to 40, respectively.