P. Duverneuil

Two‐Dimensional Modeling of Low Pressure Chemical Vapor Deposition Hot Wall Tubular Reactors I . Hypotheses, Methods, and First Results

A new two-dimensional model taking into account hydrodynamics and mass transport with chemical reactions has been developed. The system of partial differential equations has been solved by finite differences procedures and a Gauss-Seidel algorithm. The case of pure polysilicon deposition is first described, taking into account the chemical species produced by silane pyrolysis, i.e., disilane and silylene

Chemical vapor deposition of SnO2 coatings on Ti plates for the preparation of electrocatalytic anodes

Abstract SnO2 coatings have been deposited by metal-organic chemical vapor deposition (MOCVD) on Ti plates using SnEt4 and O2 as reactive gas mixture. The thickness, morphology and microstructure of these coatings are controlled by the growth conditions. The deposition process has been used for the preparation of Ti/IrOx/SnO2 electrodes that were tested for the anodic oxidation of organic pollutants in industrial wastewater. These anodes exhibit a high overpotential for oxygen evolution and a good efficiency for the elimination of total organic carbon (TOC) from wastewater. Electrochemical impedance measurements were used to characterize the activity of the interface SnO2/aqueous media as a function of time during the oxidation process. The influence of the grain size, thickness and surface pre-treatment of the Ti substrate on the electrocatalytic properties is discussed.

Two‐Dimensional Modeling of Low Pressure Chemical Vapor Deposition Hot Wall Tubular Reactors II . Systematic Analysis of Pure and Phosphorus In Situ Doped Polycrystalline Silicon Depositions

Using the new two-dimensional model, described in the preceding article, which takes into account hydrodynamics, mass transport, and chemical reactions, the special case of phosphorus in situ doped polysilicon deposition are simulated and analyzed. The main contribution to the deposition of in situ phosphorus-doped polysilicon must now be attributed to silylene

Thermal and kinetic modelling of low-pressure chemical vapour deposition hot-wall tubular reactors

A mathematical model, describing the complete behaviour of low-pressure chemical vapour deposition (LPCVD) reactors has been developed. The improvement of this model over existing ones reported in the literature consists in that it gives a more detailed account of the temperature profile on the solid surfaces in an LPCVD reactor. On the other hand, the proposed model is considerably simpler than most others already proposed, since it utilizes a continuously stirred tank reactor approach for mass balances. This approximation makes the model only relevant but, nevertheless, particularly useful to the case of depositions naturally leading to uniform layers across each wafer and, therefore, to the case of pure polycrystalline deposition from silane. A systematic use of this model, combined with a comparison of its predictions with experimental data, has served as an incentive for further investigations of other chemical vapour depositions systems (in situ boron-doped polysilicon and semi-insulating polyoxide silicon depositions) and is of interest for the choice of new industrial processes.

Simulation of silicon deposition from SiHCl3 in a CVD barrel reactor at atmospheric pressure

Abstract The growth rate of epitaxial Si in a chemical vapor deposition barrel reactor was investigated. Trichlorosilane was employed as a precursor diluted in H2 carrier gas at 1 atm reactor pressure. The growth rates and the fluid dynamics were analyzed using a software package, ESTET. Finally, it was demonstrated that the Soret effect in our experimental conditions, influences up to 5% the predictive rate of deposition obtained when this effect was neglected.

Making of specific electrodes by CVD

Abstract SnO 2 thin films were deposited on Ti substrates by metal-organic chemical vapor deposition using the reactive gas mixture SnEt 4 -O 2 to prepare electrode materials. A kinetic study of the growth process has been carried out as a function of the deposition parameters and a simulation model of the growth rate was used to obtain rapidly thickness variations on flat substrates of less than 2% along the axis of the reactor over an isothermal length of 150 mm long. This deposition process has been used for the preparation of SnO 2 /Ti electrodes subsequently used in the electrochemical treatment of industrial wastewater.

Comments on the influence of the entrance zone in LPCVD reactors for in situ phosphoros-doped polysilicon deposition

The objective of the article is to present several original results, obtained through the combined approach of experiments and two-dimensional modeling, which could suggest solutions in order to improve the choice of the operating conditions in an LPCVD (low-pressure chemical vapor deposition) reactor for this kind of deposition

Analysis and Modelling of the LPC VD Annular Reactor

Abstract This paper presents the results of our work on a new type of CVD reactor, annular reactor. This equipment is able to deposit pure silicon and also in-situ phosphorus doped silicon on a large number of substrates

Three dimensional modeling of LPCVD vertical cold wall reactors

Abstract A three dimensional model for cold wall CVD reactors is presented, involving the resolution of momentum, heat and mass transfer equations with homogeneous and heterogeneous chemical reactions. The contribution of each chemical species to the deposition of the thin solid films produced and the influence of the operating conditions on these contributions are described and analysed.

MODELING OF PURE AND IN SITU DOPED POLYCRYSTALLINE SILICON DEPOSITION UN LPCVD REACTORS

ABSTRACT A global mathematical model of Low Pressure Chemical Vapor Deposition (LPCVD) reactors has been developed. The use of the model can be of practical interest for both the choice of operating conditions and reactor design. Calculations of the wafer temperature have been carried out providing better insights in the radiation heat transfer phenomena, occurring inside the reactor. The presence of injectors, often used in the industrial practice, has also been taken into account. This model turned out to be successful for predicting growth rates of pure and in situ boron doped polycrystalline silicon. The case of in situ phosphorus doped poly-Si, involving complex homogeneous chemistry and a consequent radial nonuniformity, needs a more appropriate local approach, which is briefly discussed.