Chemistry of SiO2 Plasma Deposition

1990 ◽  
Vol 204 ◽  
Author(s):  
Donald L. Smith ◽  
Andrew S. Alimonda ◽  
Tzu-Chin Chuang
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Plasma Deposition ◽  
Electron Trapping ◽  
Electrical Characteristics ◽  
Rf Power ◽  
Film Analysis ◽  
Minor Contribution ◽  
Thermal Oxide ◽  
A Minor

ABSTRACTThe chemistry of SiO2 deposition from N20-SiH4 plasma was studied by line-ofsight mass spectrometry coupled with film analysis. If rf power and N2O flow are sufficient, more than enough O atoms are available to convert all of the SiH4 to SiO2, and good electrical characteristics (IV and breakdown) are then obtained with or without He dilution. Gas-phase SimHn(OH)p species make a minor contribution to the deposition and may be the source of the OH in the film. Both [OH] and electron trapping are much larger than for thermal oxide, with or without He dilution.

Relation between Growth Precursors and Film Properties for Plasma Deposition of a-Si:H at Rates up to 100 Å/s

2000 ◽  
Vol 609 ◽  
Author(s):  
W.M.M. Kessels ◽  
A.H.M. Smets ◽  
J.P.M. Hoefnagels ◽  
M.G.H. Boogaarts ◽  
D.C. Schram ◽  
...  
Keyword(s):  
Substrate Temperature ◽  
Deposition Rate ◽  
Surface Reaction ◽  
Film Growth ◽  
Plasma Deposition ◽  
Reaction Probability ◽  
Film Properties ◽  
Deposition Rates ◽  
Minor Contribution ◽  
A Minor

ABSTRACTFrom investigations on the SiH3 and SiH radical density and the surface reaction probability in a remote Ar-H2-SiH4 plasma, it is unambiguously demonstrated that the a-Si:H film quality improves significantly with increasing contribution of SiH3 and decreasing contribution of very reactive (poly)silane radicals. Device quality a-Si:H is obtained at deposition rates up to 100 Å/s for conditions where film growth is governed by SiH3 (contribution ∼90%) and where SiH has only a minor contribution (∼2%). Furthermore, for SiH3 dominated film growth the effect of the deposition rate on the a-Si:H film properties with respect to the substrate temperature is discussed.

Observation of 13C rearrangement in [13C2]biphenylene formed from benzyne on pyrolysis of [1,6-13C2]phthalic anhydride and [2a,3-13C2]benzocyclobutenedione

1984 ◽  
Vol 37 (8) ◽  
pp. 1643 ◽  
Author(s):  
M Barry ◽  
RFC Brown ◽  
FW Eastwood ◽  
DA Gunawardana ◽  
C Vogel
Keyword(s):  
Mass Spectrometry ◽  
Sulfur Dioxide ◽  
Isotopic Composition ◽  
Gas Phase ◽  
Phthalic Anhydride ◽  
Carbon Skeleton ◽  
Hydrogen Shift ◽  
Thermal Elimination ◽  
A Minor

Examination of [13C2]biphenylene formed by gas phase pyrolysis of doubly labelled benzyne precursors shows that the principal pyrolytic process leads to overall 1,2→1,3 rearrangement of the C6H4 carbon skeleton either in an intermediate C7H4O before decarbonylation or in benzyne itself. A minor process involves an apparent 1,3-hydrogen shift. [1,2-13C2]Ethyne-1,2-diylbistrimethylsilane was acylated with 3-(2,5-dihydro-1,1-dioxothien- 2-yl)propanoyl chloride and the resulting ketone was desilylated to yield 5-(2,5-dihydro-1,l-dioxo-thien-2-yl)[1,2-13C2]pent-1-yn-3-one. Thermal elimination of sulfur dioxide and cyclization followed by dehydrogenation yielded [7,7a-13C2]-2,3-dihydro-1H-inden-1-one which was oxidized and dehydrated to give [3a,4-13C2]isobenzofuran-1,3-dione. This doubly labelled phthalic anhydride was diluted to approximately 5% 13C2 and the resulting material was converted via benzenediazonium- 2-carboxylate into biphenylene at 84�, and pyrolysed at 830� to yield biphenylene, and a sample diluted to 7.5% was converted into [2a,3-13C2]benzocyclobutenedione which was pyrolysed at 650�, 750� and 830� to yield further samples of biphenylene. The biphenylene samples were examined by mass spectrometry at 20 eV to determine their isotopic composition and by 13C n.m.r. spectroscopy to determine the distribution of labelling.

The thermolysis of ε-halodisilanes: a preference for 1,2-Si Si → O rearrangement or Si—O cleavage over Si=O bond formation

1996 ◽  
Vol 74 (8) ◽  
pp. 1470-1479 ◽  
Author(s):  
Christopher Roos ◽  
Graham A. McGibbon ◽  
Michael A. Brook
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Driving Force ◽  
Bond Formation ◽  
Molecular Ions ◽  
Gas Chromatography Mass Spectrometry ◽  
Major Route ◽  
A Minor ◽  
Group Migration ◽  
Silyl Group Migration

Tris(trimethylsilyl)-2,2,2-trifluoroethoxysilane 6, tris(trimethylsilyl)-2-fluoroethoxysilane 7, and tris(trimethylsilyl)-2-chloroethoxysilane 8 were synthesized and characterized by 1H, 13C and 29Si NMR, IR spectroscopy, and EI and CI mass spectrometry. Thermodynamic considerations would suggest that, as a result of the driving force provided by the formation of a Si—F or Si—CI bond, the thermolyses of these compounds would lead to the formation of bis(trimethylsilyl)silanone 4. To examine this question, gas chromatography–mass spectrometry was as used a detection technique for products resulting from the high-pressure thermolyses of 6–8. The elimination of (Me3Si)3SiCl appears to be the major thermolytic pathway of decomposition for 8 at ambient or higher pressures, although it is accompanied by the formation of other products, some of which could have arisen from the addition of various halosilanes to a silanone. Neither 6 nor 7 thermolyzed cleanly; the former compound was essentially unreactive under the thermolysis temperatures used (850 °C). Of the products produced in the thermolysis of 7, no evidence for the formation of the silanone was obtained. Independently, mass spectrometry was used to study unimolecular reactions of molecular ions derived from 6–8. The major route to solitary ions appears to involve a 1,2-trimethylsilyl migration from Si to O (9 → 10) prior to decomposition, for example, of the m/z 346 parent ion in the decomposition of 6. The preparation of the ionized silanone may be a minor pathway. Some of the other fragmentation pathways for 6–8 are discussed. Key words: gas phase thermolysis, ion rearrangements, silyl group migration, silanone, halosilane.

scholarly journals The Influence of La and Ce on Microstructure and Mechanical Properties of an Al-Si-Cu-Mg-Fe Alloy at High Temperature

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 384
Author(s):  
Andong Du ◽  
Anders E. W. Jarfors ◽  
Jinchuan Zheng ◽  
Kaikun Wang ◽  
Gegang Yu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Temperature ◽  
Intermetallic Phases ◽  
High Temperature Strength ◽  
Thermal Expansion Mismatch ◽  
Strengthening Mechanisms ◽  
High Temperature Mechanical Properties ◽  
Minor Contribution ◽  
A Minor

The effect of lanthanum (La)+cerium (Ce) addition on the high-temperature strength of an aluminum (Al)–silicon (Si)–copper (Cu)–magnesium (Mg)–iron (Fe)–manganese (Mn) alloy was investigated. A great number of plate-like intermetallics, Al11(Ce, La)3- and blocky α-Al15(Fe, Mn)3Si2-precipitates, were observed. The results showed that the high-temperature mechanical properties depended strongly on the amount and morphology of the intermetallic phases formed. The precipitated tiny Al11(Ce, La)3 and α-Al15(Fe, Mn)3Si2 both contributed to the high-temperature mechanical properties, especially at 300 °C and 400 °C. The formation of coarse plate-like Al11(Ce, La)3, at the highest (Ce-La) additions, reduced the mechanical properties at (≤300) ℃ and improved the properties at 400 ℃. Analysis of the strengthening mechanisms revealed that the load-bearing mechanism was the main contributing mechanism with no contribution from thermal-expansion mismatch effects. Strain hardening had a minor contribution to the tensile strength at high-temperature.

Mass Spectrometry and Gas-Phase Chemistry of Anilines

ChemInform ◽  
2007 ◽  
Vol 38 (30) ◽  
Author(s):  
Marcos N. Eberlin ◽  
Daniella Vasconcellos Augusti ◽  
Rodinei Augusti
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Gas Phase Chemistry ◽  
Phase Chemistry
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