Single adatom diffusion in homo- and heteroepitaxies of Si and Ge on (100)-2x1 surfaces modeled by MEAM

The energy barriers for single adatom diffusion of Si and Ge on the (100)-2 x1 reconstructed surfaces of Si and Ge are calculated by Modified Embedded Atom Method (MEAM). The results for Si/Si are compared with other theoretic al works. The activation energies for diffusion along and across the dimer row are 0.27 and 0.60 eV for Si/Si and 0.22 and 0.48 eV for Ge/Ge, respecti vely. Anisotropic diffusion is also suggested for Ge/Si. However, larger ac tivation energy for Ge/Si than Si/Si and small diffusion anisotropy for Si/ Ge are contradictory results to experiments, which suggests that the treatm ent of the Si-Ge interaction should be improved. (C) 2001 Elsevier Science B.V. All rights reserved.