Cobalt silicide formation inside surface defects of a silicon substrate

The formation process of a CoSi2 layer after vacuum Co film deposition on an Si single crystal surface was investigated by means of scanning tunneling microscope (STM), SEM and RHEED. The pinholes which cause different kinds of film roughness show mark's of melting processes, It is shown that in the limits of the theory of mechanochemical activity the activation energy of the silicide formation is lower inside the defect than in the bulk silicon. Therefore, the exothermic reaction of silicidation starts earlier which leads to a heating of the CoSi product. We calculated the time dependencies of the temperature inside the defect for different areas of its surface using the layer growth diffusion model and proved that the temperature increases up to the melting point at a certain critical area. (C) 2002 Elsevier Science B.V. All rights reserved.