Diffusion of Cu over a clean Si(111) surface

Auger electron spectroscopy and low-energy electron diffraction were used t o study the diffusion of Cu over an atomically clean Si(111) surface. It is found that the diffusion gives rise to concentration distributions of copp er with a sharp boundary and to the formation of the Si(111)-"5 x 5"-Cu sur face phase. It is shown that transport of copper over the Si(111) surface o ccurs via the solid-state spreading process. The temperature dependence of the coefficient of Cu diffusion over the Si(111) surface was determined as given by D-Cu = 10(4)exp(-1.9/kT) cm(2)/s. (C) 2001 MAIK "Nauka / Interperi odica".