Letter: Thermal Decomposition of Methyltrichlorosilane,Dimethyldichlorosilane and Methyldichlorosilane by Flash Pyrolysis Vacuum Ultraviolet Photoionization Time-of-Flight Mass Spectrometry
Restricted accessLetterFirst published online October, 2014
Letter: Thermal Decomposition of Methyltrichlorosilane,Dimethyldichlorosilane and Methyldichlorosilane by Flash Pyrolysis Vacuum Ultraviolet Photoionization Time-of-Flight Mass Spectrometry
The thermal decompositions of methyltrichlorosilane (MTS) (CH3SiCl3), dimethyldichlorosilane (Si(CH3)2Cl2), and methyldichlorosilane (SiHCH3Cl2) were studied at temperatures from ∼1000 K to 1500 K on a short timescale of 20 μs to 100 μs using flash pyrolysis vacuum ultraviolet single-photon ionization time-of-flight mass spectrometry. The pyrolysis of MTS proceeds primarily via Si–C bond homolysis to form the SiCl3 and methyl radicals. At elevated temperatures, SiCl2 production from secondary decomposition of SiCl3 becomes more important, and other pyrolysis pathways of MTS, including C–H bond fission and HCl elimination make minor contributions. The pyrolysis of Si(CH3)2Cl2 occurs mainly by the sequential loss of methyl radicals, ultimately forming a significant amount of SiCl2. Si(CH3)2Cl2 also has two minor decomposition channels at higher temperatures, molecular elimination of CH4 to form SiCH2Cl2 and of CH3Cl to form SiCH3Cl. The pyrolysis of SiHCH3Cl2 mainly undergoes sequential CH3 and H loss and/or molecular elimination of CH4 to form SiCl2, while molecular elimination of HCl to form SiCH3Cl also contributes. SiCl2 is produced in significant concentrations in the pyrolysis of all three molecules, suggesting that it is an important intermediate in SiC chemical vapor deposition from chloroorganosilanes.
LiuC.X.YangY.Q.LuoX., “Influence of CH3SiC3 consistency on growth process of SiC film by kinetic Monte Carlo method”, J. Wuhan University of Technology Mater. Sci. Ed.27, 871 (2012). doi: https://dx-doi-org.web.bisu.edu.cn/10.1007/s11595-012-0565-5
LoumagneF.LanglaisF.NaslainR.SchammS.DorignacD.SevelyJ., “Physicochemical properties of SiC-based ceramics deposited by low-pressure chemical-vapor-deposition from CH3SiCl3–H2”, Thin Solid Films254, 75 (1995). doi: https://dx-doi-org.web.bisu.edu.cn/10.1016/0040-6090(94)06237-f
8.
CagliostroD.E.RiccitielloS.R., “Model for the formation of silicon carbide from the pyrolysis of dichlorodimethylsilane in hydrogen .1. Silicon formation from chlorosilanes”, J. Am. Ceram. Soc.76, 39 (1993). doi: https://dx-doi-org.web.bisu.edu.cn/10.1111/j.1151-2916.1993.tb03687.x
9.
CagliostroD.E.RiccitielloS.R., “Model for the formation of silicon carbide from the pyrolysis of dichlorodimethylsilane in hydrogen: 2 Silicon-carbide formation from silicon and methane”, J. Am. Ceram. Soc.76, 49 (1993). doi: https://dx-doi-org.web.bisu.edu.cn/10.1111/j.1151-2916.1993.tb03688.x
10.
CagliostroD.E.RiccitielloS.R.CarswellM.G., “Analysis of the pyrolysis products of dimethyldichlorosilane in the chemical vapor-deposition of silicon carbide in argon”, J. Am. Ceram. Soc.73, 607 (1990). doi: https://dx-doi-org.web.bisu.edu.cn/10.1111/j.1151-2916.1990.tb06560.x
11.
PapasouliotisG.D.SotirchosS.V., “Experimental study of atmospheric pressure chemical vapor deposition of silicon carbide from methyltrichlorosilane”, J. Mater. Res.14, 3397 (1999). doi: https://dx-doi-org.web.bisu.edu.cn/10.1557/jmr.1999.0460
GeY.B.GordonM.S.BattagliaF.FoxR.O., “Theoretical study of the pyrolysis of methyltrichlorosilane in the gas phase. 1. Thermodynamics”, J. Phys. Chem. A111, 1462 (2007). doi: https://dx-doi-org.web.bisu.edu.cn/10.1021/jp065453q
14.
GeY.B.GordonM.S.BattagliaF.FoxR.O., “Theoretical study of the pyrolysis of methyltrichlorosilane in the gas phase. 2. Reaction paths and transition states”, J. Phys. Chem. A111, 1475 (2007). doi: https://dx-doi-org.web.bisu.edu.cn/10.1021/jp065455a
15.
GeY.B.GordonM.S.BattagliaF.FoxR.O., “Theoretical study of the pyrolysis of methyltrichlorosilane in the gas phase. 3. Reaction rate constant calculations”, J. Phys. Chem. A114, 2384 (2010). doi: https://dx-doi-org.web.bisu.edu.cn/10.1021/jp911673h
ChambreauS.D.ZhangJ.S.TraegerJ.C.MortonT.H., “Photoioinization of methyl t-butyl ether (MTBE) and t-octyl methyl ether (TOME) and analysis of their pyrolyses by supersonic jet/photoionization mass spectrometry”, Int. J. Mass Spectrom.199, 17 (2000).
ChambreauS.D.LemieuxJ.M.WangL.ZhangJ.S., “Mechanistic studies of the pyrolysis of 1,3-butadiene, 1,3-butadiene-1,1,4,4-d4, 1,2-butadiene, and 2-butyne by supersonic jet/photoionization mass spectrometry”, J. Phys. Chem. A109, 2190 (2005). https://dx-doi-org.web.bisu.edu.cn/doi:10.1021/jp045010r
SteeleW.C.StoneF.G.A.NicholsL.D., “Determination of silicon–carbon and silicon–hydrogen bond dissociation energies by electron impact”, J. Am. Chem. Soc.84, 4441 (1962). doi: https://dx-doi-org.web.bisu.edu.cn/10.1021/ja00882a014
WangL.HeY.-L., “Halogenated silanes, radicals, and cations: Theoretical predictions on ionization energies, structures and potential energy surfaces of cations, proton affinities, and enthalpies of formation”, Int. J. Mass Spectrom.276, 56 (2008). doi: https://dx-doi-org.web.bisu.edu.cn/10.1016/j.ijms.2008.07.004
26.
HochmannP.TempletP.H.WangH.T.McGlynnS.P., “Molecular Rydberg transitions .1. Low-energy Rydberg transitions in methyl halides”, J. Chem. Phys.62, 2588 (1975). doi: https://dx-doi-org.web.bisu.edu.cn/10.1063/1.430841
27.
YenchaA.J.HopkirkA.HirayaA.DonovanR.J.GoodeJ.G.MaierR.R.J.KingG.C.KvaranA., “Threshold photoelectron-spectroscopy of Cl2 and Br2 up to 35 eV”, J. Phys. Chem.99, 7231 (1995). doi: https://dx-doi-org.web.bisu.edu.cn/10.1021/j100019a004
