Silicide formation on annealing of W(100) monocrystals with thin film silicon coatings

The interaction between silicon and a W {100} single crystal during the silicon film growth and subsequent annealing of the sample is studied. The thickness of the Si films ranged from 1 to 20 monolayers. Several methods, i.e., LEED, AES and angular resolved EELS are employed, which allowed studying the surface composition, its geometry and electronic structure. It is shown that disordered silicon films grow on W{100} at room temperature and do not change until the annealing temperature attains ∼ 1000 K, when the surface structure ordering is observed due to the diffraction pattern coherent with the substrate. Further temperature increase is accompanied by alternation of several new LEED patterns and simultaneous reduction of silicon concentration in the surface layers. it is concluded from the analysis of the electron energy loss spectra of the system that annealing results in silicon formation