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

Conclusions
substrates, respectively.
The post growth annealing together with Si capping resulted in a very interesting
structure evolution and growth scenario through vacancy stacking faults
(V-SF) and circular-voids formation. The circular-voids and V-SF kinetics shows
strong dependence on the substrate temperature. During temperature ramping
up to 800 ◦ C total recrystallization and reconstruction of the grown structure has
been observed. The InAs vapor interact with Si walls and conned in the voids,
evolved nally to a nearly spherical QD shape, which results in a defect-free Si
matrix growth around the InAs QDs.
GPA 2D strain mapping derived from high-resolution TEM structure images
conrmed fully relaxed QDs with no detectable strain gradients in the Si matrix
around InAs clusters. On the other hand, anisotropic lattice distortions inside the
InAs clusters are identied, which are characterized by compressive and tensile
strain distributions in the two mapped directions, i.e. parallel and perpendicular
to the growth direction. This residual strain is discussed based on the thermal
mismatch between InAs and Si. The lattice strain is released by dislocation loops
localized along the InAs/Si interface consisting of perfect 60 ◦ -type dislocations,
while the thermal stress is released by SFs generation during cool down process.
Successful MBE growth of n-type (As 4 ) doped silicon with a controlled doping
prole and doping levels up to 7×10 17 cm −3 as well as P-N junctions characteristics
have been achieved.
The site-controlled growth of GaAs/In 0.15 Ga 0.85 As/GaAs nanostructures has
been demonstrated for the rst time with 1 µm spacing and very low nominal
deposition thicknesses, directly on pre-patterned Si without the use of SiO 2 mask.
The optimized GaP growth with best RMS values of 1.3 nm for the MBE-GaP
growth was obtained without growth stop between GaP-MEE and GaP-MBE, and
with the increased Ga growth rate from 100 nm to 300 nm during the temperature
ramping from MEE to MBE growth mode. We can conclude that the thin GaP-
MEE/Si shows great promise as a virtual substrate for III-V on Si growth. These
results are highly encouraging for the realization and integration of III-V on Si
optical devices for potential applications.
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