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Journal ArticleDOI

Catalyst Enhanced Chemical Vapor Deposition: Effects on Chemical Vapor Deposition Temperature and Film Purity

01 Oct 1997-Journal of the American Chemical Society (American Chemical Society)-Vol. 119, Iss: 39, pp 9295-9296
About: This article is published in Journal of the American Chemical Society.The article was published on 1997-10-01. It has received 22 citations till now. The article focuses on the topics: Combustion chemical vapor deposition & Ion plating.
Citations
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Journal ArticleDOI
TL;DR: The state-of-the-art achievements in selective organic synthesis indicate the appearance of a new trend of organic molecules, biologically active compounds, pharmaceutical substances and smart materials with absolute selectivity as discussed by the authors.
Abstract: The challenges of the modern society and the growing demand of high-technology sectors of industrial production bring about a new phase in the development of organic synthesis. A cutting edge of modern synthetic methods is introduction of functional groups and more complex structural units into organic molecules with unprecedented control over the course of chemical transformation. Analysis of the state-of-the-art achievements in selective organic synthesis indicates the appearance of a new trend — the synthesis of organic molecules, biologically active compounds, pharmaceutical substances and smart materials with absolute selectivity. Most advanced approaches to organic synthesis anticipated in the near future can be defined as 'atomic precision' in chemical reactions. The present review considers selective methods of organic synthesis suitable for transformation of complex functionalized molecules under mild conditions. Selected key trends in the modern organic synthesis are considered including the preparation of organofluorine compounds, catalytic cross-coupling and oxidative cross-coupling reactions, atom-economic addition reactions, methathesis processes, oxidation and reduction reactions, synthesis of heterocyclic compounds, design of new homogeneous and heterogeneous catalytic systems, application of photocatalysis, scaling up synthetic procedures to industrial level and development of new approaches to investigation of mechanisms of catalytic reactions. The bibliography includes 840 references.

179 citations

Patent
09 Apr 2008
TL;DR: In this article, the authors present compositions of matter useful as deposition agents for making structures, including thin film structures and hard coatings, on substrates and features of substrates.
Abstract: The present invention provides compositions of matter useful as deposition agents for making structures, including thin film structures and hard coatings, on substrates and features of substrates. In an embodiment, for example, the present invention provides metal complexes having one or more diboranamide or diboranaphosphide ligands that are useful as chemical vapor deposition (CVD) and/or atomic layer deposition (ALD) precusors for making thin film structures and coatings. Metal complex CVD precursors are provided that possess volitilities sufficiently high so as to provide dense, smooth and homogenous thin films and coatings.

128 citations

Journal ArticleDOI
TL;DR: In this article, Y2O3 thin films were grown onto Si(100) substrates by atomic layer deposition (ALD) using organometallic precursors, viz. tris(cyclopentadienyl)yttrium, Cp3Y, and tris (methylcyclopentadiyl) yttriu...
Abstract: Y2O3 thin films were grown onto Si(100) substrates by atomic layer deposition (ALD) using organometallic precursors, viz. tris(cyclopentadienyl)yttrium, Cp3Y, and tris(methylcyclopentadienyl)yttriu...

93 citations

Journal ArticleDOI
TL;DR: The precursors of formula [Ce(hfac)3{MeO(CH2CH2O)nMe} have been used for chemical vapor deposition (CVD) of films of cerium oxides on the substrates Si, Pt, and TiN.
Abstract: Precursors of formula [Ce(hfac)3{MeO(CH2CH2O)nMe}], 1 (n = 1), 2 (n = 2), and 3 (n = 3), and [{Ce(hfac)3}2{μ-MeO(CH2CH2O)4Me}], 4 (hfac = CF3COCHCOCF3), have been prepared and used as precursors for chemical vapor deposition (CVD) of films of cerium oxides on the substrates Si, Pt, and TiN. Thermal CVD at 450 °C with oxygen as carrier gas gave mixed Ce(III)/Ce(IV) oxides, and the main crystalline component was Ce4O7, but with fluoride impurity. The fluoride impurity was not observed if CVD was carried out using moist oxygen as carrier gas or if the as-deposited films were annealed in oxygen. Codeposition with [Y(hfac)3{MeO(CH2CH2O)2Me}] gave films of the mixed Ce(IV)Y(III) oxide Ce2Y2O7. The depositions of cerium oxides could be enhanced by use of a palladium precursor catalyst [Pd(2-methylallyl)(acetylacetonate)] and could then be carried out at 250 °C, giving films of CeO2. Under carefully controlled conditions, films of ceria-supported palladium could be prepared by this method. The films were characte...

60 citations

Journal ArticleDOI
TL;DR: CVD studies devoted to platinum and palladium deposition on planar substrates for microelectronics have clearly shown that it is possible to reach high-quality deposits at temperatures above 200 °C as discussed by the authors.
Abstract: CVD studies devoted to platinum and palladium deposition on planar substrates for microelectronics have clearly shown that it is possible to reach high-quality deposits at temperatures above 200 °C

58 citations

References
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Journal ArticleDOI
TL;DR: In this paper, X-ray diffraction and reflection high-energy electron diffraction observations reveal the heteroepitaxial growth of Y2 O3 films on Si(100) and Si(111) substrates.
Abstract: Yttria (Y2 O3 ) films have been grown on Si (100) and Si (111) substrates heated at 800 °C by vacuum evaporation. X‐ray diffraction and reflection high‐energy electron diffraction observations reveal the heteroepitaxial growth of Y2 O3 films on Si (100) and Si (111) substrates. The (111) oriented Y2 O3 films are grown directly on Si (111) substrates. The (100) oriented Y2 O3 films are grown on the thin (Y2 O3 )0.09 (ZrO2 )0.91 layer predeposited on Si (100) substrates instead of direct growth on Si (100) substrates.

115 citations

Journal ArticleDOI
TL;DR: Pulsed laser deposition (PLD) has quickly emerged as a unique tool with which to grow high quality films of complex chemical compounds as mentioned in this paper, and it is estimated that at present the number of different materials which have been deposited by PLD now exceeds two hundred.
Abstract: Pulsed laser deposition (PLD) has quickly emerged as a unique tool with which to grow high quality films of complex chemical compounds. It is estimated that at present the number of different materials which have been deposited by PLD now exceeds two hundred. Scientists have used this process primarily as a laboratory tool to deposit films of various compounds that are typically difficult to synthesize by other techniques, and then quickly evaluate the relevant material properties. Deposition techniques such as ion‐beam, rf, or dc magnetron sputtering, electron‐beam evaporation, molecular beam epitaxy, chemical vapor deposition, and metal organic chemical vapor deposition, have all achieved wide‐spread acceptance as processes with which to grow various types of electronic and optical films. In order for PLD to emerge as a real production process, it must be demonstrated that PLD is capable of depositing material over useful substrate sizes with acceptable uniformity. PLD must also compete with more establ...

103 citations

Journal ArticleDOI
TL;DR: In this article, the first surfaceselective surface-selective depositions of Pd and Ag films from metal-organic precursors were reported by in situ kinetic and spectroscopic studies conducted in ultrahigh vacuum.
Abstract: We report the first surface-selective depositions of Pd and Ag films from metal-organic precursors. We also describe mechanistic studies of this process by in situ kinetic and spectroscopic studies conducted in ultrahigh vacuum. We have studied three precursors containing the hexafluoroacetylacetonato (hfac) ligand: Pd(hfac)[sub 2] (1), Ag(hfac)(PMe[sub 3]) (2), and AF(hfac)(PMe[sub 3])[sub 2] (3). These compounds (especially 1) are reasonably volatile and sublime readily in vacuo at temperatures of 20-50[degree]C. Chemical vapor depositions from these precursors have been conducted at 200-245[degree]C both under vacuum (10[sup [minus]4] Torr) and in the presence of H[sub 2]. In the presence of H[sub 2], Pd(hfac)[sub 2] readily gives micron-thick films of pure palladium metal on glass, silicon, copper, tungsten, aluminum, and nickel at temperatures as low as 200[degrees]C. Mass spectrometic analysis of the byproducts suggests that deposition of Pd involves the reaction of Pd(hfac)[sub 2] with H[sub 2] to form hexafluoroacetylacetone (hfacH). Similar surface-independent depositions of Ag films are observed for the silver precursors under an H[sub 2] atmosphere. This redox transmetalation route may be generally applicable provided that the redox potentials are favorable and that the surface atoms can be carried away as a volatile hfac complex. 33 refs., 1 fig.

96 citations

Journal ArticleDOI
TL;DR: In this article, the synthesis of SiC (both powder and whiskers) was carried out from rice husks with and without the use of catalysts (iron, cobalt and nickel) and the introduction of the catalyst increased the reaction rate, the yield becoming up to three times that for the uncatalysed reaction and increased the proportion of β-phase from 95% to 99%.
Abstract: The synthesis of SiC (both powder and whiskers) was carried out from rice husks with and without the use of catalysts (iron, cobalt and nickel). The introduction of the catalyst increased the reaction rate, the yield becoming up to three times that for the uncatalysed reaction, and increased the proportion of β-phase from 95% to 99%. The general behaviour of the three catalysts was very similar, although nickel was the most effective from the point of view of reaction rate, and cobalt in producing larger crystal size. Analysis of the evolution of reaction rate, morphology of the whisker formed, evolution of gases during reaction, crystal size and intermetallic phases, led to a reaction mechanism based on the formation of an M-Si-C liquid phase which is essential for the nucleation and growth of the SiC whiskers.

82 citations

Journal ArticleDOI
TL;DR: The reactions of bis(hexafluoroacetylacetonato)palladium(II), Pd(hfac) 2, on copper have been studied in this paper.
Abstract: The reactions of bis(hexafluoroacetylacetonato)palladium(II), Pd(hfac) 2, on copper have been studied. Whereas multilayers of Pd(hfac)2 desorb molecularly from copper surfaces between 200 and 270 K, submonolayer coverages of Pd(hfac)2 react in a multistep sequence. At temperatures below 120 K, Pd(hfac)2 transfers its hfac ligands to the copper surface and the metal center is reduced to Pd 0 . The hfac groups adopt a variety of molecular orientations on the surface at 120 K but undergo an apparent ordering transition near 300 K that re-orients the hfac groups to an upright geometry (perpendicular to the surface plane). At low coverages on clean surfaces, further annealing results in the decomposition of the surface-bound hfac ligands to give adsorbed Pd atoms and COCF3, CF3, and fluoride species. These intermediates ultimately yield a partial monolayer of Pd atoms, a carbon (possibly graphitic) deposit, and a variety of organic products that desorb between 500 and 650 K; the desorbing flux after ionization consists of CF3COF, COCF3 ,C F 3, and CO fragments. The activation parameters for the decomposition of hfac groups on copper foils have been determined to be A ) 1.3 10 13 s -1 and Ea ) 36.8 kcal mol -1 . When Pd(hfac)2 is dosed onto copper surfaces bearing submonolayer coverages of carbon, a new reaction channel is evident: some of the hfac ligands abstract copper atoms from the surface and generate Cu(hfac)2, which desorbs when the surface is heated. The palladium atoms remain behind and diffuse into the bulk of the Cu crystal. This redox transmetalation reaction (Pd II (hfac)2 + Cu 0 f Pd 0 + Cu II (hfac)2) is the same one that is responsible for the ability of Pd(hfac)2 to effect the chemical vapor deposition of palladium selectively on copper at higher pressures. This redox transmetalation reaction is the first example of the simultaneous etching of copper and deposition of palladium.

80 citations