Gas source homoepitaxy on Si(113) - the interrelation of H-induced reconstructions and growth morphology

High-temperature. time-lapsed STM-studies are used to investigate the surface morphology and the growth mode of gas source MBE of Si on Si(113) with disilane (Si2H6) as a precursor. A varying hydrogen coverage on the growing surface caused by the dynamic equilibrium between hydrogen supply From the precursor and thermal H desorption at 480 degrees C results in several different reconstructions. Phases with (2 x 7) and (2 x 5) at a low Aux of disilane and a (2 x 2) at high flux were distinguished that consist of only two basic elements: a low-H-coverage double-row structure and the gradual insertion of high-H-coverage (2 x)-like heavy domain walls. Above H coverages resulting in the (2 x 5) larger domains of (2 x 2)separate. for which a model is suggested. Besides an anisotropic shape of the Si islands in all stages of growth, a strong influence of the H-induced reconstructions on the silicon growth mode is found. Whereas step flow dominates for the lower H-coverage structure (2 x 7) and (2 x 5), the Formation of the (2 x 2) leads to a massive nucleation of Si islands arranged in a quasi-periodic way. This difference in nucleation behaviour results in a mechanism for a layer-by-layer-like growth mode, even on a surface with a very high hydrogen coverage in contrast to Si(lll). (C) 1998 Elsevier Science B.V. All rights reserved.