Effect of Si–H Bond on the Gas-Phase Chemistry of Trimethylsilane in the Hot Wire Chemical Vapor Deposition Process

Shi, Yujun; Li, X. M.; Toukabri, R.; Tong, Ling

doi:10.1021/jp203966h

Cited by 20 publications

(45 citation statements)

References 35 publications

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“…This temperature was comparable to the one obtained with 0.12 Torr of TriMS, which was determined to be $1200 C. 14 The two new peaks at m/z 88 and 146 were attributed mainly to TMS and HMDS, respectively, in our previous study. After turning the filament on, we noticed that the intensity of these two photofragment ions started to decrease at a filament temperature of 1100 C when using 4.0 Torr of TriMS.…”

Section: Resultssupporting

confidence: 84%

“…In a previous study by our group, 14 the decomposition chemistry of TriMS on a hot W filament and the secondary reaction chemistry in a hotwire CVD reactor have been systematically investigated using single photon ionization (SPI) with a vacuum ultraviolet (VUV) laser radiation coupled with time-of-flight (TOF) mass spectrometry (MS). Under the typical deposition pressures used in hot-wire CVD (a couple of hundred milliTorr to several Torr), these reactive species undergo various reactions in the gas phase to produce the final mix of precursors that react with the substrate surface, leading to film formation.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Resultssupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

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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“…As was described in our previous study, 14,21 the room temperature 10.5 eV SPI TOF mass spectrum of DMS is predominated by the parent ion peak at m/z 60 ((CH 3 ) 2 SiH 2 + ) and its photofragment at m/z 58 ((CH 3 ) 2 Si + ). Investigation of the secondary gas-phase reactions of 0.12 Torr of DMS on a tantalum filament revealed a competition between free radical reactions and silylene−silene reactions.…”

Section: Resultssupporting

confidence: 57%

Effect of pressure on the gas-phase chemistry when using monomethylsilane and dimethylsilane in hot-wire chemical vapor deposition

ToukabriRim

ShiYujun

2015

Can. J. Chem.

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The effect of source gas pressure on the gas-phase reaction chemistry of dimethylsilane (DMS) and monomethylsilane (MMS) in the hot-wire chemical vapor deposition process has been studied by examining the secondary gas-phase reaction products in a reactor using a soft laser ionization source coupled with mass spectrometry. For DMS, the increase in sample pressure has resulted in the formation of small hydrocarbons, including ethene, acetylene, propene, and propyne. This leads to a switch from silylene dominant chemistry to a free radical dominant one with the pressure increase at low filament temperatures of 1200 and 1300°C. At the lower pressure of 0.12 Torr, the formation of 1,1,2,2-tetramethyldisilane by dimethylsilylene insertion reaction into the Si-H bond in DMS is favored over trimethylsilane produced from a free radical recombination reaction for a short reaction time. However, when the pressure is increased by 10 times, the gas-phase chemistry becomes dominated by the formation of trimethylsilane. We have demonstrated that trapping of the corresponding active intermediates by the small hydrocarbons produced in situ is responsible for the observed switch. In the study with MMS, the gas-phase chemistry is dominated by the formation of 1,2-dimethyldisilane and 1,3-disilacyclobutane at both pressures of 0.48 and 1.2 Torr. Unlike DMS, the gas-phase reaction chemistry with MMS does not involve free radicals, which are the precursors to produce small hydrocarbons. The absence of small hydrocarbons formed in situ with MMS explains the preservation in chemistry upon the increase in pressure when MMS is used as a source gas.Résumé : On a étudié dans un réacteur l'effet de la pression du gaz source sur la réaction en phase gazeuse du diméthylsilane (DMS) et du monométhylsilane (MMS) par un procédé de dépôt chimique en phase vapeur à fil chaud, en étudiant les produits secondaires dans la phase gazeuse au moyen d'un laser de faible puissance utilisé comme source d'ionisation et couplé avec un spectromètre de masse. Dans le cas du DMS, l'augmentation de la pression de l'échantillon a entraîné la formation d'hydrocarbures légers, notamment l'éthène, l'acétylène, le propène et le propyne. On en déduit que l'environnement chimique où la formation du silylène prédomine passe à un environnement chimique où la formation de radicaux libres prédomine dans lequel une augmentation de la pression s'est produite à de basses températures du filament (1200 et 1300°C). À la pression la plus faible (0,12 Torr), pendant un temps de réaction court, la formation du 1,1,2,2-tétraméthyldisilane par réaction d'insertion du diméthylsilylène dans le lien Si−H du DMS a été favorisée, par rapport à la formation du triméthylsilane issu de la réaction de recombinaison de radicaux libres. Toutefois, lorsque la pression était décuplée, la formation en phase gazeuse du triméthylsi-lane était prédominante. Nous avons démontré que le piégeage des intermédiaires réactifs par les hydrocarbures légers produits in situ est responsable du changement obse...

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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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Effect of Si–H Bond on the Gas-Phase Chemistry of Trimethylsilane in the Hot Wire Chemical Vapor Deposition Process

Cited by 20 publications

References 35 publications

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

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

Effect of pressure on the gas-phase chemistry when using monomethylsilane and dimethylsilane in hot-wire chemical vapor deposition

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

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