Ion beam sputter deposited Si0.8Ge0.2 epilayers: Lattice defects and surface topology

V. Demuth*, W. Dorsch, H. P. Strunk, M. Lyakas, M. Eizenberg, N. Mosleh, F. Meyer, C. Schwebel

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

We study growth topology and defect structure of heteroepitaxial Si0.8Ge0.2 layers grown by ion beam sputter deposition (20 keV Xe+) on (001)-Si substrates (growth rate: 1.4 Å/ s) And use transmission electron microscopy and atomic force microscopy. The sputtered surfaces are, at all growth temperatures, rather smooth (mean surface roughness < 18 Å). There is a slight tendency for improved quality at higher growth temperatures, which we attribute to the larger diffusion length of adatoms at the Si0.8Ge0.2 layer surface. The lattice defects observed in the Si0.8Ge0.2 layer can be classified into a) misfit induced defects (dislocations) and b) defects due to the bombardment of the growing film with high energetic Si and Ge atoms (defects parallel to {113} and {001} lattice planes). The origin of {113} defects is discussed in terms of point defect generation and agglomeration due to a supersaturation of point defects. At high growth temperatures (700 °C) the enhanced diffusion of point defects to the layer surface and the Si substrate reduces the supersaturation. Thus, nucleation of {113} and {001} defects is suppressed.

Original languageEnglish
Pages (from-to)431-436
Number of pages6
JournalSolid State Phenomena
Volume47-48
StatePublished - 1996
Externally publishedYes

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