Molecular beam epitaxial growth of III-V semiconductor ... - KOBRA

3.4 Challenges of Heteroepitaxial Growth of III-V on Silicon
Figure 3.4:
Energy gap versus the lattice constant of the most common III-V semiconductors
in comparison to Si. The indirect semiconductor GaP has a lattice constant
almost equal to Si, which is very encouraging for almost lattice matched-heteroepitaxy.
Figure modied according to reference [41].
plotted versus the lattice constant of the most common III-V semiconductors in
comparison to Si. GaAs as well as InP have a lattice constant larger by more than
4% than that of Si. From the values of the lattice constants in Table 3.1 one can
calculate the lattice mismatch (f) using Eq. 3.8. Where a S is the lattice constant
of the substrate and a L the lattice constant of the grown layer [31]. While GaAs
on silicon exhibit a lattice mismatch of 4.1 %, InAs on Si suers by a mismatch
of 10.4 %.
f = a L − a S
a S
(3.8)
A view at the lattice constants of dierent III-V compound semiconductors
plotted in Fig. 3.4 reveals that the indirect semiconductor GaP has a lattice
constant almost equal to that of Si with a lattice mismatch about 0.37 %, which
is very promising for a dislocation free growth of GaP layers on Si substrates.
The mismatch in Eq 3.8 may take on either sign, with some interesting differences
observed between the tensile strain, when the lattice constant of the
epi-layer is less than the lattice constant of the substrate (f> 0). On the other
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