J. Shi et al., Growth behavior and microstructure of Co-Ge films prepared on GaAs substrate by high-temperature sequential deposition, J CRYST GR, 222(1-2), 2001, pp. 235-242
The growth behavior and microstructure of Co-Ge/GaAs films prepared by the
high-temperature sequential deposition (HTSD) method have been investigated
using X-ray diffraction, cross-sectional transmission electron microscopy,
X-ray photoelectron sepectroscopy and atomic force microscopy. Three germa
nides were formed in the films at temperatures ranging from 300 to 600 degr
eesC, Polycrystalline CoGe with poor crystallinity was formed at 300 degree
sC, On the other hand, epitaxial Co5Ge7 were formed at 400 and 500 degreesC
, The epitaxial orientations for the Co5Ge7 films formed at 400 and 500 deg
reesC are [0 0 1] (1 0 0) Co(5)Ge(7)parallel to [1 1 0] (0 0 1) Ge parallel
to [1 1 0] (0 0 1) GaAs and [1 0 0] (0 0 1) Co(5)Ce(7)parallel to [1 1 0]
(0 0 1) Ge parallel to [1 1 0] (001) GaAs, respectively. Then, at 600 degre
esC polycrystalline CoGe2 was formed in the film. Based on the experimental
results, the solid-state reaction mechanism for Co-Ge binary system and th
e epitaxial growth mode for Co5Ge7 are discussed. (C) 2001 Elsevier Science
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