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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 ...
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.
Thin-film deposition is a process applied in the semiconductor industry to grow electronic materials, in the aerospace industry to form thermal and chemical barrier coatings to protect surfaces against corrosive environments, in optics to impart the desired reflective and transmissive properties to a substrate and elsewhere in industry to modify surfaces to have a variety of desired properties.
Reduced pressures tend to reduce unwanted gas-phase reactions and improve film uniformity across the wafer. Ultrahigh vacuum CVD (UHVCVD) – CVD at very low pressure, typically below 10 −6 Pa (≈ 10 −8 torr). Note that in other fields, a lower division between high and ultra-high vacuum is common, often 10 −7 Pa.
The metal is heated and evaporated under vacuum. This condenses on the cold polymer film, which is unwound near the metal vapour source. This coating is much thinner than a metal foil could be made, in the range of 0.5 micrometres. [1] This coating will not fade or discolour over time.
Zinc, problematic for high vacuum and higher temperatures, present in some construction alloys, e.g. brass and some brazing alloys. Tends to poison hot cathodes and form conductive deposits on surfaces. [3] Any materials that have been zinc-coated by galvanization should be avoided, or they have the coating removed first. Magnesium; Paints
A conductive coating is needed to prevent charging of a specimen with an electron beam in conventional SEM mode (high vacuum, high voltage). While metal coatings are also useful for increasing signal to noise ratio (heavy metals are good secondary electron emitters), they are of inferior quality when X-ray spectroscopy is employed. For this ...