14515-39-0Relevant articles and documents
Etching silicon with HF-HNO3-H2SO4/H 2O mixtures- unprecedented formation of trifluorosilane, hexafluorodisiloxane, and Si-F surface groups
Lippold, Marcus,Boehme, Uwe,Gondek, Christoph,Kronstein, Martin,Patzig-Klein, Sebastian,Weser, Martin,Kroke, Edwin
, p. 5714 - 5721 (2013/02/25)
The etching behaviour of sulfuric-acid-containing HF-HNO3 solutions towards crystalline silicon surfaces has been studied over a wide range of H2SO4 concentrations. For mixtures with low sulfuric acid concentration, NO2/N2O4, N 2O3, NO and N2O have been detected by means of FTIR spectroscopy. Increasing concentrations of nitric acid lead to high etching rates and to an enhanced formation of NO2/N2O 4. Different products were observed for the etching of silicon with sulfuric-acid-rich mixtures [c(H2SO4) > 13 mol L -1]. Trifluorosilane and hexafluorodisiloxane were identified by FTIR spectroscopy as additional reaction products. In contrast to the commonly accepted wet chemical etching mechanism, the formation of trifluorosilane is not accompanied by the formation of molecular hydrogen (according to Raman spectroscopy). Thermodynamic calculations and direct reactions of F 3SiH with the etching solution support an intermediate oxidation of trifluorosilane and the formation of hexafluorodisiloxane. The etched silicon surfaces were investigated by diffuse reflection FTIR and X-ray photoelectron spectroscopy (XPS). Surprisingly, no SiH terminations were observed after etching in sulfuric-acid-rich mixtures. Instead, a fluorine-terminated surface was found.
Gas-phase oxidation of vinyltrifluorosilane with nitrogen dioxide under the action of a pulse CO2 laser
Dement'ev,Koshlyakov,Chesnokov
experimental part, p. 624 - 634 (2011/02/16)
A chemical reaction between C2H3SiF3 and NO2 induced by radiation from a pulse CO2 laser was studied by mass spectrometry and IR spectroscopy. The composition of gaseous products was determined. A macrokinetic approach was developed to study bimolecular reactions initiated by pulsed IR radiation. The procedure developed allowed us to answer the question of whether the test reaction occurs under conditions when the molecules of only one reactant are vibrationally excited or under conditions of equal vibrational temperatures. The use of this approach to the reaction between C2H3SiF3 and NO 2 demonstrated that its acceleration was due to the equilibrium heating of the system.
F3SiSH and (F3Si)2S: Conflicting observations resolved by unambiguous syntheses
Beckers, Helmut,Buerger, Hans
, p. 1217 - 1224 (2008/10/08)
The reaction between liquid F3SiI and red HgS mainly yields the disilylsulfane (F3Si)2S and, in smaller amounts, hitherto unknown (F3SiS)2SiF2. These fluorosilylsulfanes have different thermal stabilities. (F3Si)2S is a versatile precursor for F3Si derivatives, and at ambient temperature it is stable, while (F3SiS)2SiF2 decomposes rapidly. F3SiSH has been obtained, along with F3SiBr, by selective cleavage of one of the Si-S bonds in (F3Si)2S with HBr in the liquid phase and was for the first time unambiguously characterized. Contrary to previous reports, (F3Si)2O rather than (F2SiS)2 is formed when SiF4 is passed over SiS2 at 1298 K in a quartz tube. Raman and infrared spectra of (F3Si)2S, F3SiSH and its deuterated derivative F3SiSD have been measured and assigned to vibrational fundamentals. Multinuclear NMR spectra have been recorded. Wiley-VCH Verlag GmbH, 2001.
