A mechanistic study of gas-phase reactions with 1,1,3,3-tetramethyl-1,3-disilacyclobutane in the hot-wire chemical vapor deposition process

Tong, Ling; Shi, Yujun

doi:10.1016/j.tsf.2009.01.058

Cited by 21 publications

(22 citation statements)

References 20 publications

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“…In this technique, radical species are produced from material gases on heated metal surfaces without co-producing ionic or metastable excited species. In order to make clear the decomposition and ejection mechanisms, many studies have been carried out to identify the radical species produced [3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Although it has been rather difficult to produce oxidizing radicals, we have recently shown that atomic oxygen can be produced efficiently by the catalytic decomposition of O 2 , NO, N 2 O, and NO 2 on a heated Ir filament [7,8].…”

Section: Introductionmentioning

confidence: 99%

Catalytic Decomposition of H2O(D2O) on a Heated Ir Filament to Produce O and OH(OD) Radicals

Umemoto¹,

Kusanagi²

2009

TOCPJ

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Production of O atoms, H(D) atoms, and OH(OD) radicals was confirmed in the catalytic decomposition of H 2 O(D 2 O) on a heated Ir filament by laser spectroscopic techniques, such as vacuum-ultraviolet laser-induced fluorescence. The highest steady-state OH density achieved was 2 10 11 cm -3 . The filament temperature dependences of the radical densities were not Arrhenius-type, in contrast to the results on the decomposition of H 2 and O 2 . Especially, OH(OD) density decreased with the increase in the filament temperature over 2100 K. The decomposition process changes from the production of H+OH(D+OD) to that of 2H+O(2D+O) with the increase in the catalysis temperature. This change in the exit channel could not be reproduced by model calculations using the CHEMKIN software package when Arrhenius-type temperature dependences were assumed for the elementary-step rate constants on surfaces. It is necessary to assume that the desorption energy of OH(OD) is surface coverage dependent.

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Section: Introductionmentioning

confidence: 99%

Catalytic Decomposition of H2O(D2O) on a Heated Ir Filament to Produce O and OH(OD) Radicals

Umemoto¹,

Kusanagi²

2009

TOCPJ

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“…This is clearly visible in Fig. To our knowledge, this is the first time methane formation has been confirmed when using either open-chain alkylsilanes 14,20,21 or four-membered-ring (di)silacyclobutanes 19,[23][24][25][26] as an independent precursor gas in the hot-wire CVD process. With 4.0 Torr of TriMS, new peaks at m/z 16, 28, 40, and 42 were observed.…”

Section: A Formation Of Methane and Other Small Hydrocarbon Moleculesmentioning

confidence: 56%

Effect of trimethylsilane pressure on hot-wire chemical vapor deposition chemistry using vacuum ultraviolet laser ionization mass spectrometry

Toukabri

Shi

2013

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Detecting free radicals during the hot wire chemical vapor deposition of amorphous silicon carbide films using single-source precursors J. Vac. Sci. Technol. A 24, 542 (2006); 10.1116/1.2194023 Vacuum ultraviolet mass-analyzed threshold ionization spectroscopy of hexafluorobenzene: The Jahn-Teller effect and vibrational analysisIn this study, the authors investigated the effect of sample pressure on the reaction chemistry of trimethylsilane (TriMS) in the hot-wire chemical vapor deposition (CVD) process. The secondary gasphase reaction products were examined in a reactor with varying TriMS pressures. The reaction products were analyzed using a laser ionization source with a vacuum ultraviolet wavelength of 118 nm, coupled with mass spectrometry. By increasing TriMS pressure, methane formation was observed. To our knowledge, this is the first successful use of either open-chain alkylsilanes or four-membered-ring (di)silacyclobutane molecules as an independent precursor gas in the hot-wire CVD reactor to achieve methane formation. Our results showed that methane was formed mainly from the radical chain reactions with minor contributions from molecular elimination. The increase in the sample pressure also led to the formation of other small hydrocarbon molecules including acetylene, ethene, propyne, and propene. The formation of hydrogen molecules was enhanced when the sample pressure was increased. In addition, the change in the sample pressure had a direct effect on the radical recombination and disproportionation reactions. This is reflected in the different behavior assumed by the main products from these two types of reactions, i.e., tetramethylsilane, hexamethyldisilane from the former, and three methyl-substituted disilacyclobutanes from the latter. The trapping of free radicals resulting from the in-situ produced ethene and propene molecules is responsible for the observed difference.

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“…In the decomposition of H 2 O, the production of OH and H is major at low catalyst temperatures, but H and O production becomes more dominant at high temperatures [37]. As for organosilicon compounds, selective and efficient decomposition is possible [51][52][53][54][55][56][57]. The decomposition paths are different from those in thermal decomposition.…”

Section: Discussion and Future Prospectsmentioning

confidence: 99%

Gas-phase diagnoses in catalytic chemical vapor deposition (hot-wire CVD) processes

Umemoto

2015

Thin Solid Films

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a b s t r a c tRadical species play key roles in chemical vapor deposition (CVD) processes, including catalytic CVD (hot-wire CVD), and evaluating their densities in the gas phase is important in understanding the underlying mechanisms and controlling the processes. There are many diagnosis techniques to detect radical species. Among them, photon-in-photon-out techniques, including one-and two-photon laser-induced fluorescence and photoabsorption, can be utilized under the low vacuum conditions typical in CVD processes. Highly sensitive, quantitative, state-specific, real-time, and non-intrusive detection is possible with these techniques; even spatial resolution can be obtained in some cases. At the same time, however, we should know the drawbacks and the limitations of such techniques. A compilation of the radical species detected so far in catalytic CVD processes is presented in a table.

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A mechanistic study of gas-phase reactions with 1,1,3,3-tetramethyl-1,3-disilacyclobutane in the hot-wire chemical vapor deposition process

Cited by 21 publications

References 20 publications

Catalytic Decomposition of H2O(D2O) on a Heated Ir Filament to Produce O and OH(OD) Radicals

Catalytic Decomposition of H2O(D2O) on a Heated Ir Filament to Produce O and OH(OD) Radicals

Effect of trimethylsilane pressure on hot-wire chemical vapor deposition chemistry using vacuum ultraviolet laser ionization mass spectrometry

Gas-phase diagnoses in catalytic chemical vapor deposition (hot-wire CVD) processes

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