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Elementary reaction
About: Elementary reaction is a research topic. Over the lifetime, 2972 publications have been published within this topic receiving 76110 citations.
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TL;DR: In this article, Peev et al. used a single power-law expression, rate 5 k [SiH2Cl2] 049 [NH3] 046 (Freundlich adsorpbtion isotherm), to fit to experimental data and no gas-phase reactions are considered.
Abstract: Silicon nitride, Si 3N4, films have broad industrial applications, particularly in semiconductors and integrated circuit technology 1 One common way for depositing the films is the reaction of dichlorosilane (DCS, SiH2Cl2) with ammonia (NH3) Optimization of the film deposition and properties often requires knowledge of gas-phase and surface reaction kinetics The commonly used approach for deriving a mechanism and kinetics of chemical vapor deposition (CVD) is based on experimental results combined with reasonable assumptions The reaction rate parameters of the resulting gas-phase reactions and semiempirical deposition reactions are then fit to experimental film growth rate data in reactor simulations 2-5 Such an approach, although useful, has serious limitations due to the lack of understanding of the reaction mechanism on a molecular level Fundamental understanding of deposition chemistry can aid in implementation of new technologies and in obtaining films of high quality with respect to their structure and properties 6 A few kinetic models available in the literature for silicon nitride deposition 2-5,7 are based on different assumptions about the mechanism of gas-phase and surface reactions Surface reactions have been treated by assuming various forms for the conversion of adsorbed gas-phase reactants and intermediates into the final Si 3N4 film without considering possible elementary reactions In the model suggested by Peev et al 3 a single power-law expression, rate 5 k [SiH2Cl2] 049 [NH3] 046 (Freundlich adsorpbtion isotherm), has been used to fit to experimental data and no gas-phase reactions are considered Roenigk and Jensen 2 have included gas-phase decomposition of DCS into dichlorosililene and hydrogen into their kinetic models, Eq 1, in order to explain film nonuniformities and growth rate changes across the wafer during low pressure CVD growth The formation of aminochlorosilane (ACS, SiH2(Cl)NH2) via direct reaction of DCS with ammonia, Eq 2, was also considered as an alternative Under the low pressure conditions studied, inclusion of this bimolecular reaction “gives less quantitative agreement with experimental data” 2 SiH2Cl2 r SiCl2 1 H2
23 citations
TL;DR: Using polarography to monitor both selenide and oxygen, it is found the reaction exhibits complex kinetics, including autoaccelerating behavior and the generation of reactive intermediates capable of inducing reactions in other substances present.
23 citations
TL;DR: In this paper, the rate coefficient of the reaction CN + O 2 → NCO + O (R3) was varied to match the measured and calculated concentration profiles, and the determined rate coefficient was found to be in good agreement with the result reported by Louge and Hanson in Int. J. Kin. 16: k 3 = 4.9 × 10 12 cm 3 mol -1 s -1
23 citations
TL;DR: In this paper, the role of the torque due to the reactant-reactant potential and that due to solvent- reactant interactions in four A+BC→AB+C reactions in the gas phase and in solution is investigated by molecular dynamics simulations.
Abstract: Orientational steric effects in four A+BC→AB+C reactions in the gas phase and in solution are studied by molecular dynamics simulations. We investigate the role of the torque due to the reactant-reactant potential and that due to solvent-reactant interactions. The time scales for the development of the rotational energy and of the orientation needed for reaction are computed, the latter in terms of a BC angular correlation function
23 citations
TL;DR: In this article, the authors investigated the chelotropic addition reaction with different levels of theory (B3LYP, CASSCF, CCSD(T), G2M) and different basis sets.
Abstract: The chelotropic addition reaction (1): singlet vinylidene + acetylene → methylenecyclopropene (MCP), was investigated using different levels of theory (B3LYP, CASSCF, CCSD(T), G2M) and different basis sets (6-31G(d,p), 6-311G(d,p), 6-311++G(3df,3pd), cc-pVTZ). The concerted reaction is spontaneous at room temperature (activation enthalpy of 3 kcal mol−1) and strongly exothermic (ΔE = −64 kcal mol−1; ΔH(298) = −59 kcal mol−1). Analysis of the reaction mechanism with the help of the Unified Reaction Valley approach reveals a complicated sequence of structural and electronic changes, which can be best described by partitioning the mechanism into seven phases: (1) van der Waals, (2) electrophilic attack, (3) biradical, (4) allene, (5) carbene, (6) ring closure, and (7) MCP formation phase. In the transient regions from one phase to the next, structures are located that possess properties of hidden transition states (TSs) or hidden intermediates, i.e. by variation of the electronic nature or the environment of...
23 citations