Large-scale molecular dynamics simulations of TiN/TiN(001) epitaxial film growth

Edström, Daniel; Sangiovanni, Davide; Hultman, Lars; Petrov, I.; Greene, J. E.; Chirita, Valeriu

doi:10.1116/1.4953404

Cited by 33 publications

(20 citation statements)

References 42 publications

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“…In Eq. (19), h(x, t) is the surface height at position x at time t, ν 4 and λ 4 are constants, and F is a Gaussian white noise, representing the randomness accompanying the deposition of particles. Thus, Eq.…”

Section: Roughness and Scaling In The Multilayer Growth Regimementioning

confidence: 99%

Modeling of nonequilibrium surface growth by a limited-mobility model with distributed diffusion length

Martynec

Klapp

2019

Phys. Rev. E

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Kinetic Monte-Carlo (KMC) simulations are a well-established numerical tool to investigate the time-dependent surface morphology in molecular beam epitaxy (MBE) experiments. In parallel, simplified approaches such as limited mobility (LM) models characterized by a fixed diffusion length have been studied. Here, we investigate an extended LM model to gain deeper insight into the role of diffusional processes concerning the growth morphology. Our model is based on the stochastic transition rules of the Das Sarma-Tamborena (DT) model, but differs from the latter via a variable diffusion length. A first guess for this length can be extracted from the saturation value of the meansquared displacement calculated from short KMC simulations. Comparing the resulting surface morphologies in the sub-and multilayer growth regime to those obtained from KMC simulations, we find deviations which can be cured by adding fluctuations to the diffusion length. This mimics the stochastic nature of particle diffusion on a substrate, an aspect which is usually neglected in LM models. We propose to add fluctuations to the diffusion length by choosing this quantity for each adsorbed particle from a Gaussian distribution, where the variance of the distribution serves as a fitting parameter. We show that the diffusional fluctuations have a huge impact on cluster properties during submonolayer growth as well as on the surface profile in the high coverage regime. The analysis of the surface morphologies on one-and two-dimensional substrates during sub-and multilayer growth shows that the LM model can produce structures that are indistinguishable to the ones from KMC simulations at arbitrary growth conditions.

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Section: Roughness and Scaling In The Multilayer Growth Regimementioning

confidence: 99%

Modeling of nonequilibrium surface growth by a limited-mobility model with distributed diffusion length

Martynec

Klapp

2019

Phys. Rev. E

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“…The 100 -oriented edges are particularly relevant during TiN(001) film growth at relatively low N/Ti flux ratios and high ( 1200 K) temperatures, as observed by scanning tunneling microscopy and CMD simulations [50][51][52]. AIMD results were obtained at temperatures (T ) between 1200 and 2400 K for two different island sizes.…”

Section: A Aimd Simulationsmentioning

confidence: 99%

“…However, determination of descent pathways for ceramic materials such as TM nitrides is considerably more challenging due to the simultaneous presence of metal and nonmetal elements, which present a variety of bonding interactions (ionic, covalent, and metallic [55,89,90]) as well as surface morphology and N/TM stoichiometry that strongly depend on synthesis conditions [51,52,[91][92][93].…”

Section: Ti Adatom Descent From Tin/tin(001) Islandsmentioning

confidence: 99%

Effects of surface vibrations on interlayer mass transport: Ab initio molecular dynamics investigation of Ti adatom descent pathways and rates from TiN/TiN(001) islands

et al. 2018

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We carried out density-functional ab initio molecular dynamics (AIMD) simulations of Ti adatom (Ti ad ) migration on, and descent from, square TiN 100 epitaxial islands on TiN(001) at temperatures (T ) ranging from 1200 to 2400 K. Adatom-descent energy barriers determined via ab initio nudged-elastic-band calculations at 0 Kelvin suggest that Ti interlayer transport on TiN(001) occurs essentially exclusively via direct hopping onto a lower layer. However, AIMD simulations reveal comparable rates for Ti ad descent via direct hopping vs push-out/exchange with a Ti island-edge atom for T 1500 K. We demonstrate that this effect is due to surface vibrations, which yield considerably lower activation energies at finite temperatures by significantly modifying the adatom push-out/exchange reaction pathway.

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“…Molecular simulation [12][13][14][15] has gained wide application in the research of material properties in recent years with the fast advancement of computer technology. Molecular dynamics (MD) is an indispensable computational tool for studying the microstructure and surface morphological evolution of coatings and thin films upon varying incident flux compositions [16,17] and energies [18][19][20]. MD simulations allow the structure and properties of molecular systems to be analyzed via statistical thermodynamics [18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Molecular Simulations of Sputtering Preparation and Transformation of Surface Properties of Au/Cu Alloy Coatings Under Different Incident Energies

Zhang

Tian

Peng

2019

Metals

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The surface properties of coatings during deposition are strongly influenced by temperature, particle fluxes, and compositions. In addition, the precursor incident energy also affects the surface properties of coatings during sputtering. The atomistic processes associated with the microstructure of coatings and the surface morphological evolution during sputtering are difficult to observe. Thus, in the present study, molecular dynamics simulation was employed to investigate the surface properties of Au/Cu alloy coatings (Cu substrate sputtering by Au atoms) with different incident energies (0.15 eV, 0.3 eV, 0.6 eV). Subsequently, the sputtering depth of the Au atoms, the particle distribution of the Au/Cu alloy coating system, the radial distribution function of particles in the coatings, the mean square displacement of the Cu atoms in the substrate, and the roughness of the coatings were analyzed. Results showed that the crystal structure and the sputtering depth of Au atoms were hardly influenced by the incident energy, and the incident energy had little impact on the motion of deep-lying atoms in the substrate. However, higher incident energy resulted in higher surface temperature of coatings, and more Au atoms existed in the coherent interface. Moreover, it strengthened the motion of Cu atoms and reduced the surface roughness. Therefore, the crystal structure of coatings and the motions of deep-lying atoms in the substrate are not influenced by the incident energy. However, the increase in incident energy will enhance the combination of coatings and the base while optimizing the surface structure.

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Large-scale molecular dynamics simulations of TiN/TiN(001) epitaxial film growth

Abstract: Large-scale classical molecular dynamics (CMD) simulations of epitaxial TiN/TiN(001) thin film growth at 1200 K are carried out using incident flux ratios N/Ti = 1, 2, and 4.

Cited by 33 publications

References 42 publications

Modeling of nonequilibrium surface growth by a limited-mobility model with distributed diffusion length

Modeling of nonequilibrium surface growth by a limited-mobility model with distributed diffusion length

Effects of surface vibrations on interlayer mass transport: Ab initio molecular dynamics investigation of Ti adatom descent pathways and rates from TiN/TiN(001) islands

Molecular Simulations of Sputtering Preparation and Transformation of Surface Properties of Au/Cu Alloy Coatings Under Different Incident Energies

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