8.1.1.1 Advantages.
•
The LPE technique allows to produce high quality (low-defect density and homogeneous
composition) crystals and interfaces between the epitaxial layers, mainly because the crystal
growth is going under conditions close to thermal equilibrium.
•
The LPE process is particularly suitable for regrowth on a chemically or physically damaged
surface, such as one that has been etched. The damaged layer on a slightly damaged surface is
wiped off by the solution and then high quality crystal grows on the cleaned surface.
•
The high growth rate makes the LPE process suitable for growing thick epitaxial layers quickly.
8.1.2
METAL-ORGANIC VAPOR-PHASE EPITAXY
Metal-Organic Vapor-Phase Epitaxy (MOVPE) occurs far from the thermal equilibrium state. There are
two possibilities of the MOVPE: atmospheric-pressure and low-pressure. In Figure
37.
we can see a basic
setup for low-pressure MOVPE.
Figure 37.: Basic setup for low-pressure MOVPE.
[4]
8.1.2.1 Advantages
•
Large-scale epitaxial growth (on 2-inch or 3-inch wafer) of an epitaxial layer of uniform
composition an composition can be easily accomplished.
•
MOVPE is suitable for the growth of thin epitaxial layers, such as those of quantum well
structures and also suitable for the mass production.
•
The interfaces between the epitaxial layers are excellent if the layers are grown sequentially.
8.1.2.2 Disadvantage
•
Regrowth on a chemically of physically damaged surface often results in a defective interface.
The epitaxial layer grows on such defective surfaces because MOVPE occurs far from the thermal
equilibrium and this often causes problems, reducing the reliability of the buried heterostructure
type of laser diodes.
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