The interconnection of oxygen-adsorbat and oxygen-silicon with subsequent diffusion of atomic oxygen into the volume in systems Sb/Si(001), alloy germanium-silicon, Cr/Si(001) and Ti/Si(001) structures are studied experimentally. Also, the initial stages of oxidation (namely, adsorption and dissociation of molecular oxygen) are considered at room temperature.
Formation mechanisms of oxides on Si(001) surface with the adsorbed monolayer covering adsorbates in a wide range of expositions in the atmosphere of molecular oxygen are studied at room temperature.
It is investigated experimentally mechanisms of creation of silicides and kinetics oxidations in systems Si(001)-Cr 1 monolayer (МL), Si(001)-Ti 1МL. The mechanisms of creation of silicides and formation of oxides and suboxides are established. The formation of chromium silicide on silicon surface is started at 400 °C. The interfacial reaction in Cr/Si(001) occurs at 400 °C and higher temperatures. It was found that island’s coverage on silicon surface is formed after its annealing. The investigation of stoichiometry shows that islands have the disilicide’s structure.
Using the experimental data, the sticking coefficient of molecular oxygen on the Si(001) surface, covered with a titanium and chromium submonolayer, is calculated. Its value is by three orders of magnitude greater than for the case of clean Si(001) surface.
It is established that titanium and chromium submonolayer films, adsorbed on the Si(001) surface, at room temperature accelerate the process of silicon oxidation. It was found that titanium on Si(001) surface stimulates the oxidation of silicon surface not so effective as in the case of chromium films.
It is shown experimentally, that the passivation of silicon surfaces with one monolayer of antimony causes saturation of surface dangling bonds and makes the surface to be inert to oxidation by molecular oxygen at room temperatures and expositions from 102 L (1 L = 10-6 Torr . s–1) to 105 L in oxygen. A submonolayer coverage of antimony on the Si(001) surface at exposures to molecular oxygen more than 106 L results in formation of both the antimony and silicon oxides. The latter has a stoichiometric content close to that of SiO2.
It is shown that the germanium stimulates processes of oxidation of silicon surface. Mainly, this is due to the surface strain which induces the oxidizing processes of silicon.
For the first time, the ionization lines (IL) Sb N4,5, IL Ti М1 and М2,3, IL Cr М2,3 have been registered using the method of ionization spectroscopy,.
Chemical states of the chromium atoms on a silicon surface can be detected using IL Cr M2,3.
It is shown that in the case of an increased exposition (more than 1L) the oxidized submonolayer Ti film in Ti/Si(001) system changes both the form and position of IL Ti M2,3. The additional IL with the energy loss 43,5 eV was observed. This indicates formation of the titanium oxide.
The chemical shift of IL Sb N4,5, equal to 2,5 eV, towards larger energy was observed, using the method of ionization spectroscopy.
