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

SURFACE SCIENCE

卷:683

Article

Persichetti, L.¹  Fanfoni, M.²  Bonanni, B.²  De Seta, M.¹  Di Gaspare, L.¹  Goletti, C.²  Ottaviano, L.³  Sgarlata, A.² 

[1] Univ Roma Tre, Dipartimento Sci, Viale G Marconi 446, I-00146 Rome, Italy

[2] Univ Roma Tor Vergata, Dipartimento Fis, Via Ric Sci 1, I-00133 Rome, Italy

[3] Univ Aquila, Dipartimento Sci Fis & Chim, Laquila, Italy

关键词: Silicon;    Germanium;    Semiconductors;    Group IV epitaxy;    Epitaxial growth;   

DOI  :  10.1016/j.susc.2019.02.002

来源: Elsevier

【 摘 要 】

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 (1 x 1) 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.

【 授权许可】

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