Andrey E. Dolbak

The initial stages of NiSi2 epitaxy on clean Si(111), Si(100) and Si(110) surfaces

The initial stages of NiSi2 epitaxy on clean Si(111), Si(100) and Si(110) surfaces caused by Ni segregation to the surface from the bulk due to the decrease of its solubility in silicon when lowering the temperature were studied by SEM, LEED and AES. There are two possible states of Ni on silicon surfaces depending on the cooling rate. These are manifested in the structure of the silicon surfaces, the sizes of epitaxial islands and their density on the surface.

Effect of adsorbed Sn on Ge diffusivity on Si(111) surface

The effect of adsorbed Sn as a surfactant on Ge diffusion on a Si(111) surface has been studied by Low Energy Electron Diffraction and Auger Electron Spectroscopy. The experimental dependence of Ge diffusion coefficients on the Si(111) surface versus temperature in the presence of adsorbed Sn atoms has been measured in the range from 300 to 650°C. It has been shown that at a Sn coverage of about 1 monolayer the mobility of Ge atoms increases by several orders of magnitude.

Ge diffusion on Si surfaces

Ge diffusion on Si(100), (111), and (110) surfaces has been studied by Auger electron spectroscopy and low energy electron diffraction in the temperature range from 600 to 800 °C. Surface diffusion coefficients versus temperature have been measured.

Mechanism of Cu transport along clean Si surfaces

Cu diffusion along clean Si(111), (110) and (100) surfaces are investigated by Auger electron spectroscopy and low energy electron diffraction. The effective diffusion coefficients of copper are measured in the temperature range from 500 to 650°C. It is shown that the Cu transport along silicon surface occurs by the diffusion of Cu atoms through Si bulk and the segregation of Cu atoms to the surface during the diffusion process. It is found that the segregation coefficients of Cu to silicon surface during the diffusion process depend on surface orientation.

Surface diffusion of Pb on clean Si surfaces

Pb diffusion on clean Si(111), (100), and (110) surfaces was studied by Auger electron spectroscopy and low energy electron diffraction in the temperature range from 100 to 300°C. It is shown that lead transport along sillicon surfaces takes place via the mechanism of solid-phase spreading with a sharp moving boundary. The temperature dependence of the Pb diffusion coefficients on Si(111), (100) and (110) surfaces have been obtained. A Si(110)-4×2-Pb surface structure has been observed for the first time.

Mechanism of copper diffusion over the Si(110) surface

The mechanism of Cu diffusion over a clean Si(110) surface was studied by Auger electron spectroscopy and low-energy electron diffraction in the temperature range from 500 to 650°C. It is shown that the Cu transport over the Si(110) surface proceeds by Cu atom diffusion through the Si bulk and Cu atom segregation at the surface during diffusion. The temperature dependence of the effective Cu diffusivities at the clean Si(110) surface was found. The results were compared to those previously found for a Si(111) surface.

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.