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Цыганенко, А. А.; Storozheva, E. N.; Manoilova, O. V.; Lesage, T.; Daturi, Marco; Lavalley, J.C.

doi:10.1023/a:1018845519727

Cited by 52 publications

(31 citation statements)

References 5 publications

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“…While the bond formation between the SiO 2 surface and the protonated amino groups of those additives takes place through hydrogen bonding, quaternary ammonium compounds (QACs) or quaternary amines, like DADMAC, can bind differently. 19,[41][42][43][44] Such quaternary amines have a permanent positive charge with a structure R 4 N + , and, hence can interact electrostatically with the negative species present on a SiO 2 surface at all pH values as shown in Fig. 7.…”

Section: P39mentioning

confidence: 99%

Ceria-Based Slurries for Non-Prestonian Removal of Silicon Dioxide Films

Korkmaz

Babu

2014

ECS J. Solid State Sci. Technol.

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A slurry with a non-Prestonian dependence on the polishing pressure can help in minimizing dishing and erosion during shallow trench isolation chemical mechanical planarization. Here, we show that ceria-based slurries containing diallyldimethylammonium chloride (DADMAC) yield a non-Prestonian blanket film polish rate with a low threshold pressure (1-2 psi) when polishing plasma-enhanced chemical vapor (PECVD) tetraethylorthosilicate (TEOS) deposited oxide as well as thermal oxide films. The polishing mechanism of this non-Prestonian slurry was investigated by a series of experiments involving zeta potential measurements, thermogravimetric analysis (TGA) and UV-vis spectroscopy and it was shown that more DADMAC molecules are adsorbed on silica particles (as oxide film representatives) than on ceria particles and the binding strength between DADMAC and silica is much higher than that with ceria surface. Shallow trench isolation (STI) is an ubiquitous complimentary metal-oxide semiconductor isolation process technology. Deposition of an isolation stack that contains 3 to 10 nm thick 1,2 thermally grown pad oxide on top of a silicon substrate followed by the deposition of either plasma-enhanced chemical vapor deposition (PECVD) or low-pressure chemical vapor deposition (LPCVD) nitride layer (10 to 30 nm) 1 is the first step in the STI process. In the next step, active areas and isolation fields are determined by patterning the silicon nitride and silicon dioxide pad layers on the silicon substrate, followed by etching of trenches into the silicon substrate using the oxide/nitride stack as a mask. The trenches are then filled with oxide, employing high density plasma-enhanced chemical vapor deposition (PECVD) process using tetraethylorthosilicate (TEOS) as the source of silicon, because of its high gap-filling capacity. The deposited oxide not only fills the trenches but also generates an overfill, which needs to be removed. This is achieved through planarization of the oxide film topography by chemical mechanical planarization (CMP) using a slurry that produces a high oxide and very low nitride removal rates (RRs).In this STI process, major concerns include dishing within the oxide features resulting from over-polish as well as the erosion of the underlying nitride film and, in some cases, the details of the corner rounding near active areas. Therefore, optimization of the CMP process is crucial in order to achieve complete removal of the oxide on top of the nitride film with good planarity and uniformity and to avoid erosion and dishing during the CMP process. 3,4 One method that can be used to minimize dishing and erosion during STI CMP is to control the polishing performance by using a slurry that shows a non-Prestonian polishing behavior. Non-Prestonian behavior occurs when there is a non-linear relationship between applied polishing pressures and resulting polishing rates. Here we consider only the effect of pressure and not that of the rotational velocity on the blanket film polish rates.Several models were di...

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Section: P39mentioning

confidence: 99%

Ceria-Based Slurries for Non-Prestonian Removal of Silicon Dioxide Films

Korkmaz

Babu

2014

ECS J. Solid State Sci. Technol.

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“…This highlights that this silanol behaves in a similar way as silanol groups of pure amorphous silica materials, [17] namely that those with neighboring Al atoms via SiÀOÀAl bridges do not help the protonation of nitrogenated molecules. As shown by adsorption energies, the interaction strength roughly follows the order of basicity of the molecules: CO !…”

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confidence: 93%

Acidity of Amorphous Silica–Alumina: From Coordination Promotion of Lewis Sites to Proton Transfer

Chizallet

Raybaud

2010

ChemPhysChem

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Due to their combined Lewis and Brønsted acidities, amorphous silica-alumina (ASA) are widespread supports for multifunctional heterogeneous catalysts in fine chemistry, [1] petrochemical refining [2] and biomass conversion, [3] from the laboratory scale to the industrial plant. [4,5] These materials are moreover suspected in H-USY zeolites.[6] Due to their amorphous nature and despite improvement achieved by magic-angle spinning (MAS) NMR, [7] the local environment of the acid sites remains strongly debated. Zeolite-like bridging SiÀ(OH)ÀAl groups are sometimes invoked, [8,9] but are questioned by several other authors. [10,11] Silanols bonded to low-coordinated aluminum atoms by a SiÀOÀAl bridge have been proposed as most acidic Brønsted sites on ASA surfaces, depending on the number and coordination of aluminum atoms.[12] Trombetta et al.[10] moreover suggested that upon interaction with a basic probe molecule, silanols in the vicinity of threefold-coordinated aluminum atoms could form an additional bond between the oxygen of the silanol and the threefold-coordinated aluminum atom, which is contradicted by Crepeau et al. [12] on the basis of CO adsorption experiments. An open debate thus remains on the identification of the structure of Brønsted sites on ASA surfaces, and on their behavior during the proton transfer step.Earlier, we proposed the first model for ASA surfaces, from periodic density functional theory (DFT) calculations combined with force-field molecular dynamics.[13] Herein, the question of the nature of the Brønsted acid sites on this surface model and of behavior of such sites in the presence of molecules of various basic strengths (CO, pyridine, lutidine and ammonia) is addressed, so as to unravel the origin of the Brønsted acidity of ASA.The ASA periodic surface model was obtained by simulating the contact of g-Al 2 O 3 (100) with a silica film, stable SiÀOH groups being further obtained by gradual hydration of the surface model. The amount and nature of OH groups present on the ASA surface model primarily depends on the temperature and on the water pressure in the reactive medium. For typical reaction temperatures around 200-400 8C and water pressures lower than 1 bar, surface models exhibiting q OH values of 5.4 and 6.4 OH nm À2 can be considered as representative of the real surface state (see the Supporting Information, S1 and S2). Herein, we focus on four relevant sites, depicted in Figure 1.1) For q OH = 6.4 OH mn À2 , a bridging SiÀ(OH)ÀAl site that has a SiÀOÀAl angle of 122.28 (Figure 1 a) is present. Contrary to zeolite-like bridging OH groups, the aluminum atom is pentacoordinated and the hydroxyl exhibits hydrogen-bond donor character. 2) On the surface model with q OH = 5.4 OH mn À2, one silanol bonded to three aluminum atoms (two Al VI and one Al V ) via structural SiÀOÀAl bridges is considered, comparable to the type of sites invoked by CrØpeau et al.[12] (Figure 1 b) with the restriction that Al III (proposed by them) is not stable on our surface model. We call this site Sila...

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“…The Brönsted acidity of the three hydroxyl protons increases in the order Si-OH-Al > Al-OH > Si-OH, with the bridging hydroxyl proton being the strongest acid. [53][54][55][56] Therefore, the basic media interacts with the bridging hydroxyl protons more than the other protons and the surface of zeolite 4A becomes more negatively charged. Hence, the adsorption behavior can be explained by the electrostatic interaction between the negatively charged surface and the positively charged lysine.…”

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confidence: 99%

Immobilization of L-Lysine on Zeolite 4A as an Organic-Inorganic Composite Basic Catalyst for Synthesis of α,β-Unsaturated Carbonyl Compounds under Mild Conditions

Zamani¹,

Rezapour²,

Kianpour³

2013

Bulletin of the Korean Chemical Society

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Lysine (Lys) immobilized on zeolite 4A was prepared by a simple adsorption method. The physical and chemical properties of Lys/zeolite 4A were investigated by X-ray diffraction (XRD), FT-IR, BrunauerEmmett-Teller (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-vis. The obtained organic-inorganic composite was effectively employed as a heterogeneous basic catalyst for synthesis of α,β-unsaturated carbonyl compounds. No by-product formation, high yields, short reaction times, mild reaction conditions, operational simplicity with reusability of the catalyst are the salient features of the present catalyst.

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Cited by 52 publications

References 5 publications

Ceria-Based Slurries for Non-Prestonian Removal of Silicon Dioxide Films

Ceria-Based Slurries for Non-Prestonian Removal of Silicon Dioxide Films

Acidity of Amorphous Silica–Alumina: From Coordination Promotion of Lewis Sites to Proton Transfer

Immobilization of L-Lysine on Zeolite 4A as an Organic-Inorganic Composite Basic Catalyst for Synthesis of α,β-Unsaturated Carbonyl Compounds under Mild Conditions

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