TITLE:
Epitaxial Ge Growth on Si(111) Covered with Ultrathin SiO2 Films
AUTHORS:
Alexander A. Shklyaev, Konstantin N. Romanyuk, Alexander V. Latyshev
KEYWORDS:
Ge/Si Heterostructures; Epitaxial Growth; Surface Morphology; Scanning Tunneling Microscopy
JOURNAL NAME:
Journal of Surface Engineered Materials and Advanced Technology,
Vol.3 No.3,
July
10,
2013
ABSTRACT:
The epitaxial growth
of Ge on Si(111) covered with the 0.3 nm thick SiO2 film is studied
by scanning tunneling microscopy. Nanoareas of bare Si in the SiO2 film are prepared by Ge deposition at a temperature in the range of 570℃-650℃ due to the formation of
volatile SiO and GeO molecules. The surface morphology of Ge layers grown
further at 360℃-500℃ is composed of facets and
large flat areas with the Ge(111)-c(2 × 8) reconstruction which is typical of
unstrained Ge. Orientations
of the facets, which depend on the growth temperature, are identified. The growth at
250℃-300℃ produces continuous
epitaxial Ge layers on Si(111). A comparison of the surface morphology of Ge
layers grown on bare and SiO2-film covered Si(111) surfaces shows a
significantly lower Ge-Si intermixing in the latter case due to a reduction in
the lattice strain. The found approach to reduce the strain suggests the
opportunity of the thin continuous epitaxial Ge layer formation on Si(111).