Reconstruction of (100) diamond surfaces using molecular dynamics with combined quantum and empirical forces

Skokov, Sergei; Carmer, C. S.; Weiner, Brian; Frenklach, Michael

doi:10.1103/physrevb.49.5662

Cited by 63 publications

(38 citation statements)

References 39 publications

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“…Therefore, we obtained normal-mode frequencies by repeating the calculations using smaller clusters, modeled after C 9 H 12 examined in our previous studies, [17][18][19]34 where in most cases all atoms were allowed to relax. The small-cluster calculations were performed using standard MOPAC subroutines.…”

Section: Methodsmentioning

confidence: 99%

Surface Migration in Diamond Growth

Frenklach

Skokov

1997

J. Phys. Chem. B

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Growth of diamond has usually been discussed without invoking any form of surface diffusion. Our recent theoretical results identified, however, that bridging CH 2 and CCH 2 groups and radical vacancies can migrate on diamond {100} surfaces. The present work further explores migration of hydrogen atoms, bridging groups, and surface radicals, investigating the migration in two dimensions. The analysis is based on quantummechanical computations of potential energy barriers and vibrational frequencies, transition-state-theory evaluation of reaction rates, chemical-kinetic analysis of localized reaction networks, and idealized randomwalk calculations of migration lengths. It is demonstrated that migration of hydrogen atoms and the bridging groups is nearly isotropic in two directions, along dimer rows and along dimer chains, while migration of surface radicals introduces distinct anisotropy to the overall character of surface diffusion. In their entirety, the results substantiate the governing role of surface migration in chemical vapor deposition of diamond.

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Section: Methodsmentioning

confidence: 99%

Surface Migration in Diamond Growth

Frenklach

Skokov

1997

J. Phys. Chem. B

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“…Zhang et al 15 reported that the dihydride phase is energetically favored over the monohydride phase relative to H desorption, while it is unfavorable with respect to H 2 desorption. On the other hand, earlier studies by Yang et al 16 using a nonself-consistent tight binding model with parameters obtained from density functional theory (DFT), and by Skokov et al 17 using molecular dynamics with a semiempirical Hamiltonian, reported a (3 1):1.33H structure to be most favorable energetically. This structure consists of alternating monohydride carbon dimers and dihydride units.…”

Section: Introductionmentioning

confidence: 98%

Theoretical study of hydrogen-covered diamond (100) surfaces: A chemical-potential analysis

Hong

Chou

1997

Phys. Rev. B

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The bare and hydrogen-covered diamond (100) surfaces were investigated through pseudopotential density-functional calculations within the local-density approximation. Di erent coverages, ranging from one to two, were considered. These corresponded to di erent structures including 1 1, 2 1, and 3 1, and di erent hydrogen-carbon arrangements including monohydride, dihydride, and con gurations in between. Assuming the system was in equilibrium with a hydrogen reservoir, the formation energy of each phase was expressed as a function of hydrogen chemical potential. As the chemical potential increased, the stable phase successively changed from bare 2 1 to (2 1):H, to (3 1):1.33H, and nally to the canted (1 1):2H. Setting the chemical potential at the energy per hydrogen in H2 and in a free atom gave the (3 1):1.33H and the canted (1 1):2H phase as the most stable one, respectively. However, after comparing with the formation energy of CH4, only the (2 1):H and (3 1):1.33H phases were stable against spontaneous formation of CH4. The former existed over a chemical potential range ten times larger than the latter, which may explain why the latter, despite of having a low energy, has not been observed so far. Finally, the vibrational energies of the C H stretch mode were calculated for the (2 1):H phase.

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“…While calculations of the energetics of surface states [9][10][11][12] can provide the kinetics of individual reaction events, and predictions of surface atomic [13][14][15][16] and electronic [17][18][19] structures are useful in determining the stability of surface atomic configurations, these techniques are inapplicable to the time and length scales required to study diamond film growth. One-dimensional growth models [20][21][22][23] have been useful for verifying proposed growth mechanisms.…”

Section: Introductionmentioning

confidence: 99%

A kinetic Monte Carlo method for the atomic-scale simulation of chemical vapor deposition: Application to diamond

Battaile

Srolovitz

Butler

1997

Journal of Applied Physics

133

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We present a method for simulating the chemical vapor deposition (CVD) of thin films. The model is based upon a three-dimensional representation of film growth on the atomic scale that incorporates the effects of surface atomic structure and morphology. Film growth is simulated on lattice. The temporal evolution of the film during growth is examined on the atomic scale by a Monte Carlo technique parameterized by the rates of the important surface chemical reactions. The approach is similar to the N-fold way in that one reaction occurs at each simulation step, and the time increment between reaction events is variable. As an example of the application of the simulation technique, the growth of {111}-oriented diamond films was simulated for fifteen substrate temperatures ranging from 800 to 1500 K. Film growth rates and incorporated vacancy and H atom concentrations were computed at each temperature. Under typical CVD conditions, the simulated growth rates vary from about 0.1 to 0.8 μm/hr between 800 and 1500 K and the activation energy for growth on the {111}: H surface between 800 and 1100 K is 11.3 kcal/mol. The simulations predict that the concentrations of incorporated point defects are low at substrate temperatures below 1300 K, but become significant above this temperature. If the ratio between growth rate and point defect concentration is used as a measure of growth efficiency, ideal substrate temperatures for the growth of {111}-oriented diamond films are in the vicinity of 1100 to 1200 K.

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Reconstruction of (100) diamond surfaces using molecular dynamics with combined quantum and empirical forces

Cited by 63 publications

References 39 publications

Surface Migration in Diamond Growth

Surface Migration in Diamond Growth

Theoretical study of hydrogen-covered diamond (100) surfaces: A chemical-potential analysis

A kinetic Monte Carlo method for the atomic-scale simulation of chemical vapor deposition: Application to diamond

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