Desorption of SiO molecule from the Si(1 0 0) surface

We have studied the desorption of SiO molecule from the Si(1 0 0) surface at small oxygen coverage using the first-principles molecular dynamics. By calculating the total energies of possible oxygen adsorbed states and energy barriers among them, we determine the intermediates from which SiO molecules are desorbed with activation energies of 3.6–3.8 eV. This clarifies the nature of the slow process observed in the modulated molecular beam experiments. We present some pieces of evidence showing that the fast process is related to adsorption of molecular oxygens.