Hydrocarbon impurities in SiF4 and SiH4 prepared from it

Буланов, А. Д.; Сенников, П. Г.; Krylov, V. A.; Sorochkina, T. G.; Chuprov, L. A.; Chernova, O. Yu.; Troshin, O. Yu.

doi:10.1134/s0020168507040061

Cited by 4 publications

(2 citation statements)

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“…According to figure 4, solid silicon granulates with natural isotope composition were converted to SiF 4 gas in the first step. SiF 4 is used as a process gas for the centrifugal separation of Si for two reasons: there exists only one isotope of fluorine, namely 19 F, and SiF 4 has a sufficiently high vapour pressure at room temperature.…”

Section: Enrichment Of 28 Si In Centrifugesmentioning

confidence: 99%

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A new generation of 99.999% enriched²⁸Si single crystals for the determination of Avogadro’s constant

et al. 2017

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A metrological challenge is currently underway to replace the present definition of the kilogram. One prerequisite for this is that the Avogadro constant, N A , which defines the number of atoms in a mole, needs to be determined with a relative uncertainty of better than 2 × 10 −8 . The method applied in this case is based on the x-ray crystal density experiment using silicon crystals. The first attempt, in which silicon of natural isotopic composition was used, failed. The solution chosen subsequently was the usage of silicon highly enriched in 28 Si from Russia. First, this paper reviews previous efforts from the very first beginnings to an international collaboration with the goal of producing a 28 Si single crystal with a mass of 5 kg, an enrichment greater than 0.9999 and of sufficient chemical purity. Then the paper describes the activities of a follow-up project, conducted by PTB, to produce a new generation of highly enriched silicon in order to demonstrate the quasi-industrial and reliable production of more than 12 kg of the 28 Si material with enrichments of five nines. The intention of this project is also to show the availability of 28 Si single crystals as a guarantee for the future realisation of the redefined kilogram.

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Section: Enrichment Of 28 Si In Centrifugesmentioning

confidence: 99%

“…The content of polysilanes and disiloxanes is the largest component according to the data of a gas-chromatographic-mass-spectrometric (GC-MS) analysis at a level of 10 −3 mol mol −1 . Calcium hydride seems to be the main source of impurities, in particular carbon [19].…”

Section: Silanisation and Purification Of Silanementioning

confidence: 99%