CODEPOSITION OF Fe AND Si ON SiO₂/Si(001): RHEED STUDY

Abstract

The investigation of the codeposition process of iron and silicon (at a ratio of 1:2) on SiO₂/Si(001) surface was carried out at various substrate temperatures. A thin dioxide silicon layer (∼1 nm) was formed on Si(001) substrate by wet chemical treatment. It was found that the codeposition at room temperature results in the growth of continuous disordered film. Codeposition at 470°C initiates the interaction of Fe and Si atoms with each other on SiO₂/Si(001) surface and the formation of β-FeSi₂ polycrystalline film. At an increase of the codeposition temperature Si atoms interact with the SiO₂ layer. So, at 650°C some part of deposited silicon is consumed on the formation of voids in defect regions of SiO₂ layer and of three-dimensional (3D) epitaxial Si islands in these voids. Remaining part of adatoms is consumed on iron silicide formation. At 700°C all deposited silicon atoms are consumed on SiO₂ layer decomposition. In that way Fe atoms react with only bare silicon surface that leads to growth of 3D epitaxial α-FeSi₂ islands. It was investigated the influence of high temperature annealing on structural-phase composition of films deposited at various substrate temperatures. [DOI: 10.1380/ejssnt.2007.136]