Vacuum deposition is a group of processes used to deposit layers of material atom-by-atom or molecule-by-molecule on a solid surface. These processes operate at pressures well below atmospheric pressure (i.e., vacuum). The deposited layers can range from a thickness of one atom up to millimeters, forming freestanding structures. Multiple layers of different materials can be used, for example to form

optical coating An optical coating is one or more thin layers of material deposited on an optical component such as a lens, prism or mirror, which alters the way in which the optic reflects and transmits light. These coatings have become a key technology in th ...

s. The process can be qualified based on the vapor source; physical vapor deposition uses a liquid or solid source and

chemical vapor deposition Chemical vapor deposition (CVD) is a vacuum deposition method used to produce high quality, and high-performance, solid materials. The process is often used in the semiconductor industry to produce thin films. In typical CVD, the wafer (substra ...

uses a chemical vapor.

Description

The vacuum environment may serve one or more purposes: * reducing the particle density so that the mean free path for collision is long * reducing the particle density of undesirable atoms and molecules (contaminants) * providing a low pressure plasma environment * providing a means for controlling gas and vapor composition * providing a means for mass flow control into the processing chamber. Condensing particles can be generated in various ways: * thermal

evaporation Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...

* sputtering * cathodic arc vaporization *

laser ablation Laser ablation or photoablation (also called laser blasting) is the process of removing material from a solid (or occasionally liquid) surface by irradiating it with a laser beam. At low laser flux, the material is heated by the absorbed laser ...

* decomposition of a chemical vapor precursor,

In reactive deposition, the depositing material reacts either with a component of the gaseous environment (Ti + N → TiN) or with a co-depositing species (Ti + C → TiC). A plasma environment aids in activating gaseous species (N₂ → 2N) and in decomposition of chemical vapor precursors (SiH₄ → Si + 4H). The plasma may also be used to provide ions for vaporization by sputtering or for bombardment of the substrate for sputter cleaning and for bombardment of the depositing material to densify the structure and tailor properties ( ion plating).

Types

When the vapor source is a liquid or solid the process is called physical vapor deposition (PVD). When the source is a chemical vapor precursor, the process is called

(CVD). The latter has several variants: ''low-pressure chemical vapor deposition'' (LPCVD), plasma-enhanced chemical vapor deposition (PECVD), and ''plasma-assisted CVD'' (PACVD). Often a combination of PVD and CVD processes are used in the same or connected processing chambers.

Applications

* Electrical conduction: metallic films,

resistor A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active el ...

s, transparent conductive oxides (TCOs),

superconducting film Superconductivity is a set of physical properties observed in certain materials where electrical resistance vanishes and magnetic flux fields are expelled from the material. Any material exhibiting these properties is a superconductor. Unlike ...

s & coatings * Semiconductor devices: semiconductor films, electrically insulating films * Solar cells * Optical films:

anti-reflective coating An antireflective, antiglare or anti-reflection (AR) coating is a type of optical coating applied to the surface of lenses, other optical elements, and photovoltaic cells to reduce reflection. In typical imaging systems, this improves the effic ...

s, optical filters * Reflective coatings: mirrors, hot mirrors * Tribological coating: hard coatings, erosion resistant coatings, solid film lubricants *

Energy conservation Energy conservation is the effort to reduce wasteful energy consumption by using fewer energy services. This can be done by using energy more effectively (using less energy for continuous service) or changing one's behavior to use less service (f ...

& generation: low emissivity glass coatings, solar absorbing coatings, mirrors, solar thin film photovoltaic cells, ''smart'' films * Magnetic films: magnetic recording *

Diffusion barrier A diffusion barrier is a thin layer (usually micrometres thick) of metal usually placed between two other metals. It is done to act as a barrier to protect either one of the metals from corrupting the other.. Adhesion of a plated metal layer to it ...

gas permeation barrier Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or com ...

vapor permeation barrier In physics, a vapor (American English) or vapour (British English and Canadian English; see spelling differences) is a substance in the gas phase at a temperature lower than its critical temperature,R. H. Petrucci, W. S. Harwood, and F. G. Herr ...

solid state Solid state, or solid matter, is one of the four fundamental states of matter. Solid state may also refer to: Electronics * Solid-state electronics, circuits built of solid materials * Solid state ionics, study of ionic conductors and their u ...

diffusion barrier A diffusion barrier is a thin layer (usually micrometres thick) of metal usually placed between two other metals. It is done to act as a barrier to protect either one of the metals from corrupting the other.. Adhesion of a plated metal layer to it ...

s * Corrosion protection: * Automotive applications: lamp reflectors and trim applications * Vinyl record pressing, manufacture of gold and platinum records A thickness of less than one micrometre is generally called a thin film, while a thickness greater than one micrometre is called a coating.

References

Bibliography

* SVC, "51st Annual Technical Conference Proceedings" (2008) SVC Publications (previous proceeding available on CD) * Anders, Andre (editor) "Handbook of Plasma Immersion Ion Implantation and Deposition" (2000) Wiley-Interscience * Bach, Hans and Dieter Krause (editors) "Thin Films on Glass" (2003) Springer-Verlag * Bunshah, Roitan F (editor). "Handbook of Deposition Technologies for Films and Coatings", second edition (1994) * Glaser, Hans Joachim "Large Area Glass Coating" (2000) Von Ardenne Anlagentechnik GmbH * Glocker and I. Shah (editors), "Handbook of Thin Film Process Technology", Vol.1&2 (2002) Institute of Physics (2 vol. set) * Mahan, John E. "Physical Vapor Deposition of Thin Films" (2000) John Wiley & Sons * Mattox, Donald M. "Handbook of Physical Vapor Deposition (PVD) Processing" 2nd edition (2010) Elsevier * Mattox, Donald M. "The Foundations of Vacuum Coating Technology" (2003) Noyes Publications * Mattox, Donald M. and Vivivenne Harwood Mattox (editors) "50 Years of Vacuum Coating Technology and the Growth of the Society of Vacuum Coaters" (2007), Society of Vacuum Coaters * Westwood, William D. "Sputter Deposition", AVS Education Committee Book Series, Vol. 2 (2003) AVS * Willey, Ronald R. "Practical Monitoring and Control of Optical Thin Films (2007)" Willey Optical, Consultants * Willey, Ronald R. "Practical Equipment, Materials, and Processes for Optical Thin Films" (2007) Willey Optical, Consultants {{ref end Thin film deposition Vacuum Industrial processes

Description

Types

Applications

See also

References

Bibliography