SILICON EPITAXY ON HYDROGEN-TERMINATED SI(001) SURFACES USING THERMALAND ENERGETIC BEAMS

Silicon epitaxy on hydrogen-terminated Si(001) surfaces has been studi ed using molecular dynamics simulations. Epitaxy on the dihydride-term inated Si(001)-(1 x 1)surface is inhibited for Si atoms at thermal ene rgies due to strain hindrances created by hydrogen. At greater inciden t Si atom energies (2-10 eV), epitaxy proceeds primarily through ''sub plantation'', i.e. subsurface implantation of the incident Si atom acc ompanied by segregation of SiH2 during growth. The subplantation proba bility rises very rapidly with the incident-atom energy, a result whic h is consistent with the observation of epitaxial film growth on dihyr ide-terminated Si(001) by sputter deposition when under similar condit ions conventional molecular beam epitaxy results in amorphous Si growt h. On the hydrogen-terminated Si(001)-(2 x 1) surface, the simulation results suggest that both subplantation and hydrogen atom transfer to the incident Si atom are possible routes to epitaxy. (C) 1997 Elsevier Science B.V.