The vapor deposition process is one of the classic methods for producing thin layers as part of vacuum coating. It belongs to the group of physical vapor deposition (PVD) techniques. During the process, the starting material to be applied as a coating is heated in a vacuum chamber to such an extent that it changes into the gas phase. The energy input for heating is typically provided by resistance heating or electron beam, in rare cases also by laser radiation or induction. The vaporized material then spreads almost unhindered in a vacuum, as there are hardly any collisions with gas molecules.
When the vapor hits the substrate, it condenses like water vapor on a cold surface, creating a thin layer.
Coatings produced in this way may be porous or have low adhesive strength.