The adsorption and diffusion of Si atoms on the monohydride-terminated (001)-2 x 1 surface was investigated by using first-principles total-energy calculations. It was found that the Si adatom spontaneously separated one H atom from a surface Si dimer during adsorption, and later captured the remaining H atom of the same Si dimer during surface migration; thus leading to the most stable adsorption geometry. Migration of the Si adatom was affected by the mobility of H atoms, and was reduced in comparison with that on the bare Si surface. It was suggested that the reduction in Si diffusion had disruptive effects upon Si homo-epitaxy.

Adsorption and Diffusion of Si Atoms on the H-Terminated Si(001) Surface - Si Migration Assisted by H Mobility. J.Nara, T.Sasaki, T.Ohno: Physical Review Letters, 1997, 79[22], 4421-4