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Aluminising vacuum chamber at Mont Mégantic Observatory used for re-coating telescope mirrors. [1] 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 ...
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 ...
The VLS process takes place as follows: A thin (~1–10 nm) Au film is deposited onto a silicon (Si) wafer substrate by sputter deposition or thermal evaporation. The wafer is annealed at temperatures higher than the Au-Si eutectic point, creating Au-Si alloy droplets on the wafer surface (the thicker the Au film, the larger the droplets).
Evaporation is a common method of thin-film deposition. The source material is evaporated in a vacuum. The vacuum allows vapor particles to travel directly to the target object (substrate), where they condense back to a solid state. Evaporation is used in microfabrication, and to make macro-scale products such as metallized plastic film.
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 .
The PVD process can be carried out at lower deposition temperatures and without corrosive products, but deposition rates are typically lower. Electron-beam physical vapor deposition, however, yields a high deposition rate from 0.1 to 100 μm/min at relatively low substrate temperatures, with very high material utilization efficiency. The ...
Molecular-beam epitaxy takes place in high vacuum or ultra-high vacuum (10 −8 –10 −12 Torr). The most important aspect of an MBE process is the deposition rate (typically less than 3,000 nm per hour) that allows the films to grow epitaxially (in layers on top of the existing crystal).
Vacuum engineering is the field of engineering that deals with the practical use of vacuum in industrial and scientific applications. Vacuum may improve the productivity and performance of processes otherwise carried out at normal air pressure, or may make possible processes that could not be done in the presence of air.