LATTICE-RELAXATION OF GAAS ISLANDS GROWN ON SI(100) SUBSTRATE

Initial stage of lattice relaxation of GaAs islands grown on Si(100) s ubstrate were investigated by combination of reflection high-energy el ectron diffraction and molecular beam epitaxy. In addition to the latt ice constants in horizontal direction (a(parallel to)) to the substrat e surface, we first measured directly those in vertical one (a(perpend icular to)). At the beginning of the growth, the rapid increase of a(p arallel to) and the larger Poisson's ratios than that of bulk were obs erved. Atomic bond flexibility and extension induced by surface effect s might cause this rapid increase of a(parallel to) and large Poisson' s ratios. (C) 1997 American Institute of Physics.