Physical vapor deposition

Physical vapor deposition (PVD), sometimes called physical vapor transport (PVT), describes a variety of vacuum deposition methods which can be used to produce thin films and coatings on substrates including metals, ceramics, glass, and polymers. PVD is characterized by a process in which the material transitions from a condensed phase to a vapor phase and then back to a thin film condensed phase. The most common PVD processes are sputtering and evaporation. PVD is used in the manufacturing of items which require thin films for optical, mechanical, electrical, acoustic or chemical functions. Examples include semiconductor devices such as thin-film solar cells, microelectromechanical devices such as thin film bulk acoustic resonator, aluminized PET film for food packaging and balloons, and titanium nitride coated cutting tools for metalworking. Besides PVD tools for fabrication, special smaller tools used mainly for scientific purposes have been developed. The source material is unavoidably also deposited on most other surfaces interior to the vacuum chamber, including the fixturing used to hold the parts. This is called overshoot. Cathodic arc deposition: a high-power electric arc discharged at the target (source) material blasts away some into highly ionized vapor to be deposited onto the workpiece. Electron-beam physical vapor deposition: the material to be deposited is heated to a high vapor pressure by electron bombardment in "high" vacuum and is transported by diffusion to be deposited by condensation on the (cooler) workpiece. Evaporative deposition: the material to be deposited is heated to a high vapor pressure by electrical resistance heating in "high" vacuum. Close-space sublimation, the material, and substrate are placed close to one another and radiatively heated. Pulsed laser deposition: a high-power laser ablates material from the target into a vapor. Thermal laser epitaxy: a continuous-wave laser evaporates individual, free-standing elemental sources which then condense upon a substrate.