Dynamics of Au-adsorption-induced step bunching on a Si(001) vicinal surface studied by reflection electron microscopy

Dynamic processes of the step bunching on a Si(001) vicinal surface during Au deposition were studied by reflection electron microscopy. Due to formation of the $\mathrm{Si}\left(001\right)5\times 3.2-\mathrm{A}\mathrm{u}$ terraces and their growth the step bunching occurs and a hill and valley structure composed of (001) terraces and facets is formed. The time evolution of the (001) terrace width was analyzed for various substrate temperatures. The width develops in a form of $t^{\alpha }$ as a function of time t between 780 and 900 °C. The exponent α is $\frac{1}{4}$ at 820 °C and it increases gradually with increasing temperature and is $\frac{1}{2}$ above 870 °C. This means that the kinetics that governs the step bunching changes with increasing temperature.