Vacuum deposition processes

Two processes, referred to as sputtered and pyrolitic, were developed to produce large volumes of quality, low-e coated glass. Pyrolitic coatings are incorporated into float glass production and tend to be more durable. Sputtered systems use a stand-alone vacuum deposition process to produce coatings that are have lower emissivities but that are softer and need more protection than pyrolitic coatings. 

Soft metals such as In, Ag, Sn, Pb, and Au can lead to reasonably low friction coefficients, when used as solid lubricants, due to their low shear strength. The metals were generally applied as thin films prepared by the vacuum deposition process. Especially, in applications to the high temperature conditions where liquid lubricants fail due to the evaporation, the thin films of soft metals can provide effective protection to the surfaces in sliding. 

The stress caused by H absorbed in the course of electroless deposition is a major obstacle to the utilization of electroless films in areas of electronics where metallization of smooth surfaces is desired as an alternative to expensive vacuum deposition processes. Lacking the high-energy bombardment aspect of most vacuum depo-... 

TES are based on the steep temperature dependence of the resistance of superconducting metallic films. The useful temperature range is very narrow. These thermometers which may have a very low intrinsic noise, are fabricated by a vacuum deposition process at very low pressure and are patterned either by photolithography technique (see e.g. ref. [21]) or by micromechanical machining (see e.g. ref. [22]). The dimensionless parameter a = T/R-dR/dT defines the DC quality of a sensor. TES with a as high as 1000 have been built [23],... 

Alternative vacuum deposition processes that have recently been developed offer potential advantages such as higher deposition rates, improved adhesion, or better control of film stress or morphology. These processes include ion-beam sputtering (134), ion-cluster evaporation (135, 136), and cathodic-arc deposition (137). 

In order to find the domain of LCVD, it is necessary to compare various vacuum deposition processes chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma chemical vapor deposition (PCVD), plasma-assisted CVD (PACVD), plasma-enhanced CVD (PECVD), and plasma polymerization (PP). All of these terms refer to methods or processes that yield the deposition of materials in a thin-film form in vacuum. There is no clear definition for these terms that can be used to separate processes that are represented by these terminologies. All involve the starting material in vapor phase and the product in the solid state. 

Some important distinctive factors for these vacuum deposition processes, which have common denominator aspects, are tabulated in Table 2.1. From the operational viewpoint, these processes can be compared as shown in Table 2.2. 

Table 2.2 Comparison of Operational Factors of Vacuum Deposition Processes...

Several techniques are applicable to bulk polymer materials, such as vacuum deposition technologies. Vacuum deposition processes may be used to obtain thin polymer films that have high density, thermal stability, and insolubility in organic solvents, acids, and alkalis. These polymer deposition techniques involve in situ polymerization on a substrate surface affected by various factors. The layers can be deposited on any substrates that cannot be damaged by the vacuum processes. The following are all examples of vacuum deposition processes (Skolheim 1986 Harsanyi 20(X)) ... 

Ion-beam Assisted Deposition (IBAD) Electrode. The ion-beam assisted deposition (IBAD) technique has been previously used for a wide range of applications [69], and the detailed methodology can be found in [70]. Dual IBAD is a vacuum-deposition process that combines physical vapor deposition (PVD) with ion-beam bombardment. A vapor of coating atoms is generated with an... 

Chemistry. XY c ating is supplied as a dimer, a polymer chain only two units long. During the vacuum deposition process, the dimer powder is gradually vaporized and is recondensed onto the CCA, polymerizing with the material already deposited, lypical application is. 0005 to. 002 in. thicL... 

Figure 20.24 Illustration of the Parylene vacuum deposition process. (Reproduced with permission from Para Tech...

D. Mattox, Vacuum Deposition Processes , PF Oniine, Gardner Publications, http//www.pfonline. com. 

Fujita, K. Orihashi, Y. Itaya, A. Laser-assisted vacuum deposition process of 10-(l-pyrenyl)decanoic acid as revealed by in situ fluorescence spectroscopy. Thin Solid Films 1995, 260, 98-106. 

Diffusion pump fluids are high molecular weight materials, such as many oils and mercury, which vaporize at a reasonable temperature. A concern is the thermal and chemical stability of the fluid. Hydrocarbon oils tend to break down under heat to form low molecular weight fractions, or they may oxidize and polymerize into a vamish-like material, and therefore are not desirable for many applications. Silicone oils are much more stable with respect to temperature and oxidation and are the fluids most often used in DPs for vacuum deposition processes. 

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