Epitaxy is an emerging process technology in MEMS. The process can be used to form thin films of silicon with thicknesses of ~1µm to >100µm. The processes may be done at high temperature exposure of the substrate, and some may not or a selective deposition can also be done on the surface of the substrate. Epitaxy makes possible a high growth rate of material allowing the formation of films with thickness more than 100µm. Epitaxy is a widely used technology for producing silicon deposit on insulator (SOI) substrates.
For an ordered semiconductor crystal substrate (i.e. silicon, gallium arsenide), using the process we can continue building on the substrate with the same crystallographic orientation with the substrate acting as a seed for the deposition. If an amorphous/polycrystalline substrate surface is used, the film will also be amorphous or polycrystalline.
is Vapor Phase Epitaxy (VPE) is an important process in which a number of gases are introduced in an induction heated reactor where only the substrate is heated. The temperature of the substrate typically must be at least 50% of the melting point of the material to be deposited.