Silicon contamination during

The presence of organic contaminants as small as 1 /tm or films as thin as 1 /rm on silicon wafers during the manufacturing process of integrated circuits can be readily identified (38). These contaminants can affect the performance of the device and must be identified. Figure 3-8 shows the identification of possible Teflon contaminants. Other techniques, such as IR, X-ray diffraction, Auger and electron microprobe, are insensitive in identifying the nature of the contaminant. 

LI. Suni, G. W. Gale, and A. A. Busnaina, Dissolution kinetics for atomic, molecular, and ionic contamination from silicon wafers during aqueous processing, J. Electrochem. Soc. 146(9), 3522, 1999. 

It was demonstrated that the production of clean waxy products (i.e. free of any cobalt contamination) during large scale slurry phase Fischer-Tropsch synthesis runs, was successfully effected with cobalt catalysts that were prepared on modified supports (i.e. supports displaying inhibited dissolution behaviour in aqueous environments). As an example, the silicon modification of alumina supports was discussed in detail. 

When analyzing peptides by LC-MS, especially with nano-LC, several of the contaminants listed earlier (Section 3.2.6) are encountered, particularly those that are PEG-based and various siliconates. There are also contaminants specific to peptide analysis, such as the products of autolysis, that occur when too much trypsin is added (or when the sample contains less protein than expected) (Table 3.9a). As a rule of thumb, trypsin should be present at a concentration that is 1% of the protein to be digested. Another common contaminant is keratin that is introduced by incorrect handling of samples or by accidental contamination during sample collection (Table 3.9b). 

Metallic contamination can alter the electrical properties of the semiconductor devices. These ions can diffuse into the substrate (such as silicone oxide) during subsequent heat treatment, causing drifts in surface potential, current leakage, structural defects in vapor-grown epitaxial layers, and reduced breakdown voltage of gate oxides. 

The selection of the cure system in these applications is directed by constraints such as location of the adhesive in terms of confined space, speed and depth of cure, etc. The volumes of silicones typically applied are relatively small. In general, the uncured adhesive needs to be dispensed in a well-defined and limited area, and needs to stay in place without flowing during cure. No by-products of the cure reaction are acceptable as they may contaminate other sensitive areas of the devices. These constraints often direct the choice to the platinum-catalyzed hydrosilylation cure system that is relatively expensive. 

MRH Aluminium 10.71/33, iron 4.35/50, magnesium 10.88/40, manganese 5.06/50, sodium 5.56/55, phosphorus 7.32/25, sulfur 4.27/20 Mixtures of the chlorate with ammonium salts, powdered metals, phosphorus, silicon, sulfur or sulfides are readily ignited and potentially explosive [1], Residues of ammonium thiosulfate in a bulk road tanker contaminated the consignment of dry sodium chlorate subsequently loaded, and exothermic reaction occurred with gas evolution during several hours. Laboratory tests showed that such a mixture could be made to decompose explosively. A reaction mechanism is suggested. 

Finally, with some precursors, complete removal of contaminants can sometimes be troublesome. Consequently, some authors have chosen to use dioxygen as the reactive gas to avoid carbon contamination [62-64]. Thus, pure platinum films have been obtained on thermally oxidized silicon substrate by decomposition of [Pt(CH3)3(CpCH3)j or [Pt(K -acac)2] in ArjOj mixtures at 623 K. Pt films produced from [Pt(K -acac)2] contained less than lat% carbon, while oxygen contamination was not detectable [64]. Similarly, a significative reduction of carbon incorporation into Ru films was evidenced when oxygen was used as a reactive gas during CVD from [RuCp(CO)2]2 [62]. 

Sodium sulfate precipitation is not usually recommended for most murine MAbs because mouse/rat IgG can be degraded by the relatively high temperature (25°C) used during this procedure. If lipid contamination of ascitic fluids is a particular problem, add silicone dioxide powder (15 mg/mL), and centrifuge for 20 min at 2000g. Use the method described in Chapter 10, Section 3.2.1. 

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