ROLE OF ENERGETIC FLUX IN LOW-TEMPERATURE SI EPITAXY ON DIHYDRIDE-TERMINATED SI(001)

Epitaxial Si films were grown on the dihydride-terminated (1 X 1) Si ( 001) surface by pulsed laser deposition at substrate temperatures betw een 315 K and 625 K. Critical epitaxial thicknesses, measured by high- resolution cross-sectional transmission electron microscopy, were foun d to be smaller and to increase less rapidly with substrate temperatur e than critical epitaxial thicknesses observed for molecular beam epit axy and sputter deposition on the clean (2 x 1) Si (001) surface. In s itu reflection high-energy electron diffraction indicated that the sur face reconstruction remained (1 X 1) during growth. Ion probe time-of- flight data indicated that incident Si+ kinetic energies ranged from 1 0 eV to 135 eV. In conjunction with molecular dynamics simulations, th ese data suggest that epitaxy on the dihydride surface is enabled thro ugh transfer of surface H from surface Si to incident Si or subplantat ion of incident Si. (C) 1998 Elsevier Science S.A. All rights reserved .