Ab initio study of aluminum chemical vapor deposition from dimethylaluminum hydride: a gas phase reaction mechanism

Nakajima, Tohru; Yamashita, Koichi

doi:10.1016/s0166-1280(99)00096-2

Cited by 5 publications

(6 citation statements)

References 32 publications

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“…1, 11) If some gas-phase reactions contribute to the film growth and limit the overall rate, the slope of the deposition rate profile will not show reactor diameter dependency. Quantum chemical calculations 12) have shown that DMAH does not decompose in the gas phase, which is in agreement with the experimental observations. The quantum chemical calculations also suggest an equilibrium between the monomers and the dimers of DMAH in the gas phase around the deposition temperature and that only the monomer can react at aluminum surface.…”

Section: Mass-balance Of Aluminum Depositionsupporting

confidence: 88%

“…Al-H in a monomer strongly interacts with the alu- the difference in Gibbs free energy, G, obtained by quantum chemical calculations. 12) In the case of TMA dimer formation, the reported experimental value 15) was used.…”

Section: Mass-balance Of Aluminum Depositionmentioning

confidence: 99%

“…DMAH existed mainly as monomers in the minum surface, but it also forms dimers and trimers. 12,13) Therefore, only the monomer will react on the growing surface and dimers and trimers will not react on the surface. Hence, the analysis of this deposition rate profile requires a simulation that considers the gas-phase equilibrium between the monomer and the dimer and trimer of DMAH as well as the surface reaction of DMAH monomer.…”

Section: Deposition Rate Profile In the Reactormentioning

confidence: 99%

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Reaction Analysis of Aluminum Chemical Vapor Deposition from Dimethyl-aluminum-hydride Using Tubular Reactor and Fourier-Transform Infrared Spectroscopy: Theoretical Process Optimization Procedure (1)

Sugiyama¹,

Komiyama²,

Shimogaki³

2000

Jpn. J. Appl. Phys.

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Kinetic studies on the chemical vapor deposition (CVD) of aluminum from dimethylaluminumhydride (DMAH) were carried out to obtain the reaction model which is useful for the process optimization. Fourier-transform infrared spectroscopy (FT-IR) was used to monitor DMAH supplied to the reactor, which ensured the reliability of precursor delivery by the bubbling method. FT-IR was also used to identify the reaction product of DMAH. Aluminum deposition from DMAH yielded only trimethylaluminum (TMA). The analysis of aluminum deposition rate profile in the tubular reactor revealed that the ratelimiting step was the surface reaction of DMAH and that the surface reaction was almost of the first order with respect to DMAH concentration. The analysis took account of the monomer-dimer equilibrium of DMAH in the reactor whose existence was suggested by quantum-chemical calculations. The activation energy of approximately 80 kJ/mol was estimated from the relationship between DMAH decomposition yield and the gas residence time in the tubular reactor.

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Section: Mass-balance Of Aluminum Depositionsupporting

confidence: 88%

Section: Mass-balance Of Aluminum Depositionmentioning

confidence: 99%

Section: Deposition Rate Profile In the Reactormentioning

confidence: 99%

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Reaction Analysis of Aluminum Chemical Vapor Deposition from Dimethyl-aluminum-hydride Using Tubular Reactor and Fourier-Transform Infrared Spectroscopy: Theoretical Process Optimization Procedure (1)

Sugiyama¹,

Komiyama²,

Shimogaki³

2000

Jpn. J. Appl. Phys.

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“…Several groups have studied the dimerization of DMAlH. , We also did calculations for the DMAlH dimer and found a structure similar to that reported by Nakajima and Yamashita …”

Section: Discussionsupporting

confidence: 77%

“…The two main possibilities are (i) that DMAlH decomposes in the gas phase (either from the monomer or dimer) to give reactive species which subsequently react with the surface and (ii) that DMAlH reacts directly with the surface in a gas−surface reaction. In a recent paper, Nakajima and Yamashita used ab initio molecular orbital methods [MP2 and density functional theory (DFT)] to study gas-phase decomposition reactions. These authors studied bond-breaking processes in DMAlH and also looked at bimolecular processes in which two DMAlH molecules split off CH 4 , C 2 H 6 , and H 2 , respectively.…”

Section: Introductionmentioning

confidence: 99%

Thermal Decomposition Pathways and Rates for Dimethylaluminum Hydride

Walch

Dateo

2001

J. Phys. Chem. A

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Calculations have been carried out for the thermal decomposition of dimethylaluminum hydride (DMAlH). For each decomposition pathway, the stationary point geometries and harmonic frequencies were characterized using complete active space self-consistent field (CASSCF)/derivative methods and the correlation consistent polarized valence double-ζ (cc-pVDZ) basis set. Accurate energetics were obtained by combining the coupled cluster singles and doubles with perturbational estimate of triples [CCSD(T)] results using the cc-pVTZ basis set with an extrapolation to the basis set limit using the cc-pVDZ, cc-pVTZ, and cc-pVQZ basis sets at the Moller-Plesset second-order perturbation theory (MP2) level. The geometries, energetics, and harmonic frequencies were used to obtain rate constants using conventional transition state theory. It was found that the lowest energy pathway leads to CH 3 AlCH 2 + H 2 with a barrier of 71.1 kcal/mol, which is below the first product resulting from direct bond breaking (CH 3 Al + CH 3 at 82.2 kcal/mol). Decomposition of DMAlH dimer was also considered. The rate-limiting step here is elimination of H 2 from the DMAlH dimer, and the best estimate of the barrier for this process is 80 kcal/mol [from CCSD(T) calculations with the cc-pVDZ basis set]. This barrier is too large for this pathway to play a major role in Al chemical vapor deposition.

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Density functional study on the reactivity of oxidized aluminum surfaces: effects of adsorbed metallic atoms (Au, Cu, Ti, V)

2002

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Ab initio study of aluminum chemical vapor deposition from dimethylaluminum hydride: a gas phase reaction mechanism

Cited by 5 publications

References 32 publications

Reaction Analysis of Aluminum Chemical Vapor Deposition from Dimethyl-aluminum-hydride Using Tubular Reactor and Fourier-Transform Infrared Spectroscopy: Theoretical Process Optimization Procedure (1)

Reaction Analysis of Aluminum Chemical Vapor Deposition from Dimethyl-aluminum-hydride Using Tubular Reactor and Fourier-Transform Infrared Spectroscopy: Theoretical Process Optimization Procedure (1)

Thermal Decomposition Pathways and Rates for Dimethylaluminum Hydride

Density functional study on the reactivity of oxidized aluminum surfaces: effects of adsorbed metallic atoms (Au, Cu, Ti, V)

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