The main differences between the four most important epitaxy methods and the main problems are:
LPE (Liquid phase epitaxy)
source: solution
poor control for thin layers, limited area
VPE (Vapour phase epitaxy)
source: metal halide
thick layers are grown, no Al contained compound
MBE (molecular beam epitaxy)
needs vacuum
problems with growing materials with high vapour pressure
MOCVD (Metal organic CVD)
source: metalorganic compounds
AsH3 is very toxic
The picture below shows how the main deposition conditions (pressure and temperature) vary for each of the epitaxy type. For example, MBE requires vacuum, while VPE requires high temperatures. Each method will be discussed in detail in the next pages.