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arXiv · 1902.01207

Islanding, growth mode and ordering in Si heteroepitaxy on Ge(001) substrates structured by thermal annealing

L. Persichetti·M. Fanfoni·B. Bonanni·M. De Seta·L. Di Gaspare·C. Goletti·L. Ottaviano·A. Sgarlata
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Abstract

Si/Ge heteroepitaxial dots under tensile strain are grown on nanostructured Ge substrates produced by high-temperature flash heating exploiting the spontaneous faceting of the Ge(001) surface close to the onset of surface melting. A very diverse growth mode is obtained depending on the specific atomic structure and step density of nearby surface domains with different vicinal crystallographic orientations. On highly-miscut areas of the Ge(001) substrate, the critical thickness for islanding is lowered to about 5 ML, in contrast to the 11 ML reported for the flat Ge(001) surface, while on unreconstructed (1x1) domains the growth is Volmer-Weber driven. An explanation is proposed considering the diverse relative contributions of step and surface energies on misoriented substrates. In addition, we show that the bottom-up pattern of the substrate naturally formed by thermal annealing determines a spatial correlation for the dot sites.

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L. Persichetti, M. Fanfoni, B. Bonanni, M. De Seta, L. Di Gaspare, C. Goletti, L. Ottaviano, A. Sgarlata. 2019-02-04. Islanding, growth mode and ordering in Si heteroepitaxy on Ge(001) substrates structured by thermal annealing. https://doi.org/10.1016/j.susc.2019.02.002

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