Carbonate contamination

Reaction temperature ranges from 300 to 700°C and pressure from about 1 Torr to 1 atm. The reaction is carried out in a hydrogen atmosphere to reduce the possibility of carbon contamination. A deposition temperature > 450°C is required to eliminate the incorporation of C and O2 in the deposit.P P ]... 

Advantages of the reduction reactions are excellent microstmc-ture free of carbon contamination, and high thermal stability. The disadvantage is the need for relatively high deposition temperatures (ca. 

It is revealing to look at an example of such data in Fig. 12. The UE56/2 beamline has two nominally identical branches with replicated optical paths, but that have been used for different experiments. The measurements show a high degree of circular polarization, [531 > 98%, except near carbon K edge where the polarization reduces, but only on one branch. It is postulated that this is a consequence of carbon contamination on a beamline optic in that branch. These results demonstrate the necessity to be alert to such possible causes of degradation and to perform polarization checks where possible rather than rely on theoretical predictions. 

Me(allyl)Se 480-550 °C/R2Zn. Heavy carbon contamination (no prereaction) 77... 

Vinyl)3Sb >450 (InSb) Too stable leads to heavy carbon contamination 162,163... 

Cl2Ga(N3)(NMe3) Cold-wall CVD 1 1 GaN grown at 700 °C on Si and sapphire substrates, chlorine and carbon contamination 293... 

In all these processes, however, when manipulating samples, there may be the risk of the operator introducing some spurious carbon. To take this effect into account, samples of certified 14C concentration [65] and of dead carbon are also prepared and then measured together with the unknown samples, hence making it possible to evaluate and correct for possible systematic errors due to unwanted carbon contamination during sample preparation. 

For some elements, there are a variety of possible precursors, sulfur for instance (Figure 11). Use of metal-organic precursors, used in MOMBE or MOVPE, are possible if they are soluble in water, or a nonaqueous solvent is used. Mixed aqueous-organic solvents could improve solubility. Overall, there would be an increased probability of carbon contamination, however. One of the benefits of using inorganic salts in aqueous solutions is that the number of constituents is limited, and thus the... 

The major problem in the production of semiconductors by the decomposition of organometallics appears to be the unwanted carbon contamination of the products. 

Spectral intensities were measured as integrated peak area of each element and relative error for ratios of elemental intensity is about 10 % for aU elements except carbon. The adventitious surface carbon (contamination) was estimated at approximately 10% of the total carbon measured. The concentration of carbon is, therefore, supposed to be in relative error by ca. 20 %. 

This surface reaction would involve a change in the cyclopentadienyl hapaticity prior to SiO-H activation by the metallic species. Loss of cyclopentadiene by reductive elimination would then occur to provide an allyl palladium(ll) surface species, probably stabilized by a silanol group, in which the oxygen atom acts as a 2e donating ligand. However, when the temperature is raised significant carbon contamination has been evidenced by TPD and TPO experiments. These results are consistent with the absence of further SiO-H activation to eliminate propene [57]. 

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