Spectroscopic and thermal studies of a-SiC:H film growth: Comparison of mono-, tri-, and tetramethylsilane

Lee, Moon-Sook; Bent, Stacey F.

doi:10.1116/1.581138

Cited by 27 publications

(10 citation statements)

References 23 publications

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“…This change in the dominant gas phase intermediates from methyl radicals to silylene/silene species when moving from TMS to MMS explains the observed change in the literature from C-rich to Si-rich materials in the deposited silicon carbide thin films, as the number of Si−H bond in the precursor gas is increased. 21,48 Therefore, the study of the gas-phase reaction chemistry provides important knowledge of the gas-phase species produced prior to their deposition on a substrate surface. This helps in identifying the major contributor to the film growth and, consequently, the properties of the deposited films.…”

Section: ■ Conclusionmentioning

confidence: 99%

Dominance of Silylene Chemistry in the Decomposition of Monomethylsilane in the Presence of a Heated Metal Filament

Toukabri

Shi

2014

J. Phys. Chem. A

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The gas-phase reaction chemistry of the decomposition of monomethylsilane (MMS) has been studied in the presence of a heated metal filament in a hot-wire chemical vapor deposition (HWCVD) reactor. A 10.5 eV vacuum ultraviolet laser single-photon ionization time-of-flight mass spectrometry was employed in combination with isotope labeling and chemical trapping to examine the mechanistic details in the reaction chemistry. We have demonstrated the dominant involvement of the methylsilylene (HSiCH3) intermediate in the gas-phase reaction chemistry. Free radical and silene intermediates do not play a role. Major products are found to be H2, 1,2-dimethyldisilane (DMDS), and 1,3-disilacyclobutane (DSCB). The formation of DMDS proceeds by the insertion reaction of methylsilylene, whereas DSCB originates from the dimerization reaction of methylsilylene. Similar reaction chemistry has been observed when using the different filament materials of tungsten and tantalum in the HWCVD reactor. This indicates that changing the filament material from Ta to W does not affect the gas-phase reaction chemistry when using MMS in the HWCVD process. Finally, comparison of the reaction chemistry of MMS with those of dimethylsilane, trimethylsilane, and tetramethylsilane sheds light on the influence of increasing Si-H bonds. A switch in the dominated chemistry from free-radical short-chain reactions to silylene insertion/dimerization reactions occurs as the number of Si-H bonds increases in the four methyl-substituted silane molecules.

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Section: ■ Conclusionmentioning

confidence: 99%

Dominance of Silylene Chemistry in the Decomposition of Monomethylsilane in the Presence of a Heated Metal Filament

Toukabri

Shi

2014

J. Phys. Chem. A

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“…[15][16] Its high temperature oxidation chemistry is also of interest as it is a precursor for the flame synthesis of silicon nanoparticles 17 and Si coatings via chemical vapor deposition in semiconductor manufacturing. [18][19] Previous studies have established that the first stage of TMS oxidation involves H abstraction (e.g. by • OH) to form the (CH3)3SiCH2 • radical, [20][21][22][23][24][25][26] although further reactions of this species have not been well studied.…”

Section: Introductionmentioning

confidence: 99%

“…Validated atmospheric chemical mechanisms for TMS can then be extended to siloxanes, which also possess reactive Si–CH 3 groups. TMS is also an important volatile compound in its own right, as an emerging solvent and industrial chemical. , Its high-temperature oxidation chemistry is also of interest as it is a precursor for the flame synthesis of silicon nanoparticles and Si coatings via chemical vapor deposition in semiconductor manufacturing. , Previous studies have established that the first stage of TMS oxidation involves H abstraction ( e.g. , by • OH) to form the (CH 3 ) 3 SiCH 2 • radical. − This radical will predominantly react with O 2 and then NO in the atmosphere, but these reactions have not been well characterized.…”

Section: Introductionmentioning

confidence: 99%

Auto-Oxidation of a Volatile Silicon Compound: A Theoretical Study of the Atmospheric Chemistry of Tetramethylsilane

Silva

2020

J. Phys. Chem. A

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Volatile silicon compounds (VOSiCs) are air pollutants present in both indoor and outdoor environments. Here, tetramethylsilane (TMS) is selected as a model to study the photochemical oxidation mechanisms for VOSiCs using ab initio and RRKM theory / master equation kinetic modelling. Under tropospheric conditions the TMS radical (CH3)3SiCH2• reacts with O2 to produce a stabilized peroxyl radical which is expected to ultimately yield the alkoxyl radical (CH3)3SiCH2O•. At combustion-relevant temperatures, however, a well-skipping reaction to (CH3)3SiO• + HCHO dominates. Importantly, the (CH3)3SiCH2O• radical is predicted to rearrange to (CH3)3SiOCH2• with a very low reaction barrier, enabling an auto-oxidation process involving addition of a second O2. Subsequent oxidation reaction mechanisms of (CH3)3SiOCH2• have been developed, with the major product predicted to be the ester (CH3)3SiOCHO, an experimentally observed TMS oxidation product. The production of substantially oxygenated compounds following a single radical initiation reaction has implications for the ability of VOSiCs to contribute to ozone and particle formation in both outdoor and indoor environments. File list (2) download file view on ChemRxiv TMS Oxidation.pdf (660.08 KiB) download file view on ChemRxiv TMS supporting information combined.pdf (317.36 KiB)

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“…Although alkylsilanes, such as tetramethylsilane and methylsilane,15 have been used in the HWCVD of SiC thin films, to our knowledge, there have been no reports on using silcacyclobutane as a single source gas in HWCVD. The SCB ring structure contains a significant strain energy (70 kJ/mol),16 suggesting a possibly low decomposition temperature relative to alkylsilanes.…”

Section: Introductionmentioning

confidence: 99%

In situ diagnostics of the decomposition of silacyclobutane on a hot filament by vacuum ultraviolet laser ionization mass spectrometry

Shi¹,

Lö²,

Tong³

et al. 2007

J. Mass Spectrom.

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The gas-phase reaction products of silacyclobutane (SCB) and 1, 1-dideuterio-silacyclobutane (SCB-d(2)) from a hot-wire chemical vapor deposition (HWCVD) chamber were diagnosed in situ using vacuum ultraviolet (VUV) laser single-photon ionization (SPI) coupled with time-of-flight (TOF) mass spectrometry. The SCB molecule was found to decompose at a filament temperature as low as 900 degrees C. Both Si- (silylene, methylsilylene, and silene) and C-containing (ethene and propene) species were produced from the SCB decomposition on the filament. Ethene and propene were detected by the mass spectrometer. It is demonstrated that the formation of ethene is favored over that of propene. The experimental study of hot-wire decomposition of SCB-d(2) shows that propene is most likely produced by a process that is initiated by a 1,2-H(D) migration to form n-propylsilylene, followed by an equilibration with silacyclopropane, which then decomposes to propene. The detection of ethene in our experiment indicates that a competitive route of fragmentation exists for SCB decomposition on the filament. It has been shown that this competitive route occurs without H/D scrambling. The highly reactive silylene, silene, and methylsilylene species produced from SCB decomposition underwent either insertion reactions into the Si-H bonds of the parent molecule or pi-type addition reaction across the double and triple CC bonds. The dimerization product of silene, 1,3-disilacyclobutane, at m/z = 88 was also observed.

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Spectroscopic and thermal studies of a-SiC:H film growth: Comparison of mono-, tri-, and tetramethylsilane

Cited by 27 publications

References 23 publications

Dominance of Silylene Chemistry in the Decomposition of Monomethylsilane in the Presence of a Heated Metal Filament

Dominance of Silylene Chemistry in the Decomposition of Monomethylsilane in the Presence of a Heated Metal Filament

Auto-Oxidation of a Volatile Silicon Compound: A Theoretical Study of the Atmospheric Chemistry of Tetramethylsilane

In situ diagnostics of the decomposition of silacyclobutane on a hot filament by vacuum ultraviolet laser ionization mass spectrometry

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