Diffusion of Cu over a clean Si(111) surface

Auger electron spectroscopy and low-energy electron diffraction were used to study the diffusion of Cu over an atomically clean Si(111) surface. It is found that the diffusion gives rise to concentration distributions of copper with a sharp boundary and to the formation of the Si(111)-“5×5”-Cu surface phase. It is shown that transport of copper over the Si(111) surface occurs 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 DCu=104exp(−1.9/kT) cm2/s.