Vapor silanization

Abstract—Inelastic electron tunneling spectroscopy is used to investigate the adsorption of dimethyl-dimethoxysilane, dimethyldiethoxysilane, and dimethylvinylethoxy silane on alumina at the mono-layer level. Data obtained indicate that different adsorbed layers are produced when the silanes are introduced onto the oxide surface from solution or as a vapor. Silanes introduced in the same way onto different types of oxides suggest that alumina morphology also affects the adsorbed configuration. 

The double promoter process involves the successive application of liquid promoter solutions of vinyltrichlorosilane (VTS) and 3-chloropropyltrimethoxy-silane followed by successive cure cycles in dry N2 at 90°C after each application and before photoresist application. The double promoter process evolved because it was felt that the silane reaction with the SiOH surface groups of low temperature oxides was incomplete for a single promoter application, and because vapor silane equipment did not exist at that time. Interestingly, a double HMDS liquid promoter process failed to yield adequate adhesion as well. Later in time, the successful but somewhat complex double promoter process was replaced by the vapor phase HMDS process in the Star 1000 (or 2000) then superior resist image adhesion was obtained on all four oxide substrates with all the photoresists tested. Before the advent of the HMDS vapor priming in standalone or wafer track equipment module chambers, liquid priming solutions were widely used, especially in development areas. 

Many standard proteins lacking sufficient aromatic amino acids and thiols on their surface as e.g. urease need reactive photo cross-linking. For that purpose the protein stock solutions 5% (w/v in distilled water) is mixed with a solution of 3% (w/v) 4,4 -diazidostilbene-2,2 disulfonic acid disodiumsalt tetrahydrate (DIAS) in a ratio of 10 1 (v / v). The mixture is spin-coated onto the mirror and activated with a monolayer l-(3-aminopropyl)-methyl-diethoxysilane. Amino-silane, an efficient adhesion promoter, is applied via vapor silanization as described above. Finally the spin-coated protein film is cross-linking via irradiation with UV-light for 30 seconds (350 nm, 60 W), The application of wavelength less than 350 nm will lead to considerable DIAS decomposition, therefore DNA cross-linker devices as used above are not recommended for this method. 

When the pipette is filled with organic solution and immersed in the aqueous phase, its inner wall needs to be silanized to avoid water penetration into the pipette. This can be done by dipping the tip into chlorotrimethylsilane for 5-7 s. In this case, both the outer and inner walls of the pipette get silanized, but unlike water, organic solution is not likely to form a layer on the outer wall even though it becomes hydrophobic. A more controlled method for vapor silanization was reported recently. The pipettes were fixed in a minivacuum desiccator, which was first evacuated by the pump, and then the vapor of highly pure IV-dimethyltrimethyl silylamine was delivered from the flask to the desiccator, where the pipettes were exposed to it for about 15 min. 

Silica, fumed (polishing) A silicon oxide abrasive prepared by oxidizing vaporized silane in the gas phase. 

Viswanathan R, Thompson D L and Raff L M 1984 Theoretical investigations of elementary processes in the chemical vapor deposition of silicon from silane. Unimolecular decomposition of SiH J. Chem. Phys. 80 4230 0... 

Dielectric Deposition Systems. The most common techniques used for dielectric deposition include chemical vapor deposition (CVD), sputtering, and spin-on films. In a CVD system thermal or plasma energy is used to decompose source molecules on the semiconductor surface (189). In plasma-enhanced CVD (PECVD), typical source gases include silane, SiH, and nitrous oxide, N2O, for deposition of siUcon nitride. The most common CVD films used are siUcon dioxide, siUcon nitride, and siUcon oxynitrides. 

Oxidation. AH inorganic siUcon hydrides are readily oxidized. Silane and disilane are pyrophoric in air and form siUcon dioxide and water as combustion products thus, the soot from these materials is white. The activation energies of the reaction of silane with molecular and atomic oxygen have been reported (20,21). The oxidation reaction of dichlorosilane under low pressure has been used for the vapor deposition of siUcon dioxide (22). 

The chlorosilanes are clear Hquids that should be treated as strong acids. They react readily with water to form corrosive HCl gas and Hquid. Liquid chlorosilanes and their vapors are corrosive to the skin and extremely irritating to the mucous membranes of the eyes, nose, and throat. The nitrogen-functional silanes react with water to form ammonia, amines, or amides. Because ammonia and amines are moderately corrosive to the skin and very irritating to the eyes, nose, and throat, silylamines should be handled like organic amines. Trimethylsilyl trifluoromethanesulfonate and trimethylsilyl iodide form very corrosive acidic products. 

There are several vacuum processes such as physical vapor deposition (PVD) and chemical vapor deposition (CVD), sputtering, and anodic vacuum arc deposition. Materials other than metals, ie, tetraethylorthosiHcate, silane, and titanium aluminum nitride, can also be appHed. 

Bauer,R., Smulders,R, Geus,E., vanderPut, J., and Schoomman, J., Laser Vapor Phase Synthesis of Submicron Silicon and Silicon Nitride Powders from Halogenated Silanes, Ceram. Eng. Sci. Proc., 9(7-8) 949-956(1988)... 

Previously, trifluorosilyl groups have been bound to phosphorus (40) and silicon via the SiF (g), fluorine-bond insertion-mechanism (41). The new compound HgCSiFs) is readily hydrolyzed, but it can be stored for long periods of time in an inert atmosphere. It is a volatile, white solid that is stable up to at least 80°C. The preparation of bis(trifluoro-silyDmercury, of course, raises the possibility of (a) synthesis of the complete series of trifluorosilyl, "silametallic compounds, as had previously been done for bis(trifluoromethyl)mercury by using conventional syntheses, and (b) transfer reactions similar to those in Section II, as well as (c) further exploration of the metal-vapor approach. The compound Hg(SiF.,)j appears also to be a convenient source of difluoro-silane upon thermal decomposition, analogous to bis(trifluoromethyl)-mercury ... 

Chemical vapor deposition is distinguished from physical vapor deposition processes by the use of a chemical reaction, usually a decomposition, to create the chemical species that is deposited. An example important to the microelectronics industry is the formation of polycrystalline silicon by the decomposition of silane ... 

In an effort to restrict the location of semiconductor nanoparticles in LB films and inhibit aggregation, the formation of CdS in LB films of calixarenes was investigated [195]. Limiting areas of 3.0 nm and 1.8 nm were obtained on 0.5 mM CdCli, compatible with the cross-sectional areas of the calixarenes. Y-type LB fdms were prepared at 25 mN m on glass, quartz, and silicon. The substrates had been made hydrophobic by treatment with a silane vapor. After H2S treatment overnight in sealed jars, UV absorbance spectra and XPS data were obtained. The absorption edge for the CdS particles formed in the calixarene LB films transferred at pH 5.5 was 3.3 eV as compared with 2.7 eV for films formed in cad-... 

Silicon, like carbon, is relatively inactive at ordinary temperatures. But, when heated, it reacts vigorously with the halogens (fluorine, chlorine, bromine, cmd iodine) to form halides and with certain metals to form silicides. It is unaffected by all acids except hydrofluoric. At red heat, silicon is attacked by water vapor or by oxygen, forming a surface layer of silicon dioxide. When silicon and carbon are combined at electric furnace temperatures of 2,000 to 2,600 °C (3,600 to 4700 °F), they form silicon carbide (Carborundum = SiC), which is an Importeint abrasive. When reacted with hydrogen, silicon forms a series of hydrides, the silanes. Silicon also forms a series of organic silicon compounds called silicones, when reacted with various organic compounds. 

Tetravalent silicon is the only structural feature in all silicon sources in nature, e.g. the silicates and silica even elemental silicon exhibits tetravalency. Tetravalent silicon is considered to be an ana-logon to its group 14 homologue carbon and in fact there are a lot of similarities in the chemistry of both elements. Furthermore, silicon is tetravalent in all industrially used compounds, e.g. silanes, polymers, ceramics, and fumed silica. Also the reactions of subvalent and / or low coordinated silicon compounds normally lead back to tetravalent silicon species. It is therefore not surprising that more than 90% of the relevant literature deals with tetravalent silicon. The following examples illustrate why "ordinary" tetravalent silicon is still an attractive field for research activities Simple and small tetravalent silicon compounds - sometimes very difficult to synthesize - are used by theoreticians and preparative chemists as model compounds for a deeper insight into structural features and the study of the reactivity influenced by different substituents on the silicon center. As an example for industrial applications, the chemical vapor decomposition (CVD) of appropriate silicon precursors to produce thin ceramic coatings on various substrates may be mentioned. 

For illustrative purposes, the process of deposition of Si onto graphite is being used as an example. The 15 pm natural graphite precursors were introduced into the industrial size chemical vapor deposition reactor, where a thermal decomposition of silane (SiH4) into the silicon and hydrogen was taking place under inert gas in accordance with the equation (1) ... 

All operations should be done in a well-ventilated fume hood. Use care not to inhale vapors or get reactive silanes on your skin or in your eyes. 

Many silane coupling agents can be applied to substrates by volatilization in an enclosed chamber under heat or vacuum. In this approach, the substrate is placed within the chamber in a fashion to allow for vapor phase molecules to access all areas that are to be derivatized. This method is commonly used for silanizing glass slides or substrates that are difficult to suspend in a silane solution. Slides are often placed in racks within the chamber and all surfaces get modified... 

Chemical vapor deposition (CVD) reactions in electronics materials processing provide further examples. One is the deposition of Si from silane ... 

The hydrophilic SiO substrate)static water contact angle 0=3O°) was prepared by vapor-deposited SiO onto a Formvar substrate[4], with which an electron microscope grid(200-mesh) was covered. The relatively hydrophobic siliconized substrate(0=9O°) was also prepared by surface siliconized treatment a collodion-covered electron microscope grid was dipped into an aqueous solution of silane coupling agent. 

Significance interpretation activities, EIA, 10 236, 10 240t Si-H absorption, 20 14 Si-hybrid sealants, 22 38-40, 48t Silages, 20 863 Silane(s), 13 612, 22 489, 547 adhesion of sealant, 22 34 adhesion-promoting, 22 41 chemical vapor deposition precursor, 5 805t... 

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