epitaxy (EPI)
Epitaxy (EPI) is a term used in semiconductor manufacturing: namely, it is the growth of crystalline semiconductor crystals into ingots.
Epitaxy is about the growth of a crystal with a certain orientation on another crystal. Both crystals can have the same structural orientation. Epitaxy can be controlled to produce different semiconductor rods with different dopants. The dopants in question are those that cannot be produced by diffusion or other processes.