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

Toukabri, R.; Shi, Yujun

doi:10.1116/1.4825105

Cited by 6 publications

(6 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…From it, the ionization cross section ratio of He to TriMS has been determined to be 3.8 × 10 −4 using the 10.5 eV SPI. 25 Therefore, the contribution from EI is present, but minor, in the SPI mode used in this work. This explains the weakness of the observed parent MMS ion peak and its fragment ion peaks.…”

Section: ■ Results and Discussionmentioning

confidence: 92%

“…The amount of CH 4 varied from 2.5% to 6.25% that of H 2 . Our previous work 25 has characterized the ionization cross section of CH 4 is comparable to that of H 2 [σ(H 2 )/σ(CH 4 ) = 0.88 ± 0.04] when using the SPI mode. Considering the low intensity of the H 2 peak, CH 4 will escape detection if it is produced in a lesser amount.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…However, there is a lack of knowledge for the nature of secondary gas-phase reactions when using MMS in a HWCVD reactor. Recently, our lab has studied the gas-phase reaction chemistry of DMS, trimethylsilane (TriMS), , and tetramethylsilane (TMS) . We have shown that short free-radical chain reactions dominate the HWCVD chemistry when using TMS and TriMS, whereas the contributions from silene/silylene species are minor.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Toukabri

Shi

2014

J. Phys. Chem. A

View full text Add to dashboard Cite

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.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 92%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Toukabri

Shi

2014

J. Phys. Chem. A

View full text Add to dashboard Cite

show abstract

“…This constitutes part of our ongoing efforts on the gas-phase reaction chemistry assumed by various single-source organosilicon precursors in the process of hot-wire CVD. Our previous studies on trimethylsilane 12,13 and tetramethylsilane 14 have shown that free-radical chain reactions dominate in the secondary gasphase reactions with these two precursors when using W filaments. The reactive silene intermediates are also involved, but their contributions are minor.…”

Section: Introductionmentioning

confidence: 99%

Unraveling the complex chemistry using dimethylsilane as a precursor gas in hot wire chemical vapor deposition

Toukabri

Shi

2014

Phys. Chem. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

The gas-phase reaction chemistry when using dimethylsilane (DMS) as a source gas in a hot-wire chemical vapor deposition (CVD) process has been studied in this work. The complex chemistry is unraveled by using a soft 10.5 eV single photon ionization technique coupled with time-of-flight mass spectrometry in combination with the isotope labelling and chemical trapping methods. It has been demonstrated that both free-radical reactions and those involving silylene/silene intermediates are important. The reaction chemistry is characterized by the formation of 1,1,2,2-tetramethyldisilane (TMDS) from dimethylsilylene insertion into the Si-H bond of DMS, trimethylsilane (TriMS) from free-radical recombination, and 1,3-dimethyl-1,3-disilacyclobutane (DMDSCB) from the self dimerization of either dimethylsilylene or 1-methylsilene. At low filament temperatures and short reaction time, silylene chemistry dominates. The free-radical reactions become more important with increasing temperature and time. The same three products have been detected when using tantalum and tungsten filaments, indicating that changing the filament material from Ta to W does not affect much the gas-phase reaction chemistry when using DMS as a source gas in a hot-wire CVD reactor.

show abstract

“…15 It involves radical recombination reactions between methyl radicals as well as hydrogen abstraction reactions. In the experiments with 1.2 Torr of DMS for the temperatures of 1300 and 1400°C, the intensity ratio of ethene to propene was found to range from 0.30 to 1.37.…”

Section: Intensity (Au)mentioning

confidence: 99%

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.

Self Cite

View full text Add to dashboard Cite

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...

show abstract

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

Cited by 6 publications

References 40 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

Unraveling the complex chemistry using dimethylsilane as a precursor gas in hot wire chemical vapor deposition

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

Contact Info

Product

Resources

About