The technology of deposition under the vacuum environment has been improving over the past several years. It is generally classified into PVD (physical vapor deposition）and CVD (chemical vapor deposition).
Physical vapor deposition (PVD) is a process that involves coating the desired materials on a solid substrate.
The desired materials are physically deposited in atoms, ions, or molecules at a time under a plasma or vacuum environment. There are three main techniques applied in PVD, which are thermal evaporation, spatter evaporation and ion plating.
Thermal evaporation is a process in which the source materials (metallic or nonmetallic) are heated to vaporization then condensed as a fine film on the surface of solid substrate (metallic, semiconducting or insulating) under the vacuum.
Thermal evaporation is the least expensive PVD process and is the best process for monitoring and controlling the deposition rate.
Spatter deposition is a process that involves depositing the spattered particles by bombarding the spatter target with energetic ions which are accelerated by the plasma.
Spatter deposition technique barely generates any radiant heat during the deposition process and only needs centimeters of space between the source material (spatter target) and the substrate. In addition, Spatter plating is not limited by the melting point of source material so that it can ideally process the refractory materials such as W、Ta、C、Mo、WC、TiC.
The Ion plating technique is a combination of thermal evaporation deposition and spatter deposition. The vaporized source materials collide with the energized ions in a plasma environment or a vacuum environment where the charged ions are generated by an ion gun. After ionization, the particles of source materials are deposited on the surface of substrate.
The Ion plating process is characterized by a combination of high deposition rate of thermal vaporization and also the strong film adhesion of spatting deposition.