Effect of aluminum addition on the surface step morphology of 4H–SiC grown from Si–Cr–C solution

Mitani, Takeshi; Komatsu, Naoyoshi; Takahashi, Tetsuo; Kato, Tomohisa; Harada, Shunta; Ujihara, Toru; Matsumoto, Yuji; Kurashige, K.; Okumura, Hajime

doi:10.1016/j.jcrysgro.2015.04.032

Cited by 51 publications

(48 citation statements)

References 27 publications

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“…Hence, the height profile of a macrostep can be used to determine in which zone the surface exists. For example, the height profile of the macrostep in the case of 4H-SiC [1] is similar to the profile in the step droplet zone [45]. This suggests that the surface tension of 4H-SiC around the faceted side surface is discontinuous.…”

Section: Introductionmentioning

confidence: 74%

“…In GMPT zones I and II, since B q,eff (T) > 0, the surface free energy f (111) (q) has a form similar to Equation (1). As the temperature decreases, B q,eff (T) decreases and C q,eff (T) increases.…”

Section: Discontinuous Surface Tensionmentioning

confidence: 99%

“…The faceted macrosteps on a crystal surface are known to degrade the grown crystal [1]. Although studies have investigated methods of dispersing faceted macrosteps, an effective method has not yet been established.…”

Section: Introductionmentioning

confidence: 99%

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Disassembly of Faceted Macrosteps in the Step Droplet Zone in Non-Equilibrium Steady State

Akutsu¹

2017

Crystals

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A Wulff figure-the polar graph of the surface tension of a crystal-with a discontinuity was calculated by applying the density matrix renormalization group method to the p-RSOS model, a restricted solid-on-solid model with a point-contact-type step-step attraction. In the step droplet zone in this model, the surface tension is discontinuous around the (111) surface and continuous around the (001) surface. The vicinal surface of 4H-SiC crystal in a Si-Cr-C solution is thought to be in the step droplet zone. The dependence of the vicinal surface growth rate and the macrostep size n on the driving force ∆µ for a typical state in the step droplet zone in non-equilibrium steady state was calculated using the Monte Carlo method. In contrast to the known step bunching phenomenon, the size of the macrostep was found to decrease with increasing driving force. The detachment of elementary steps from a macrostep was investigated, and it was found that n satisfies a scaling function. Moreover, kinetic roughening was observed for |∆µ| > ∆µ R , where ∆µ R is the crossover driving force above which the macrostep disappears.

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Section: Introductionmentioning

confidence: 74%

Section: Discontinuous Surface Tensionmentioning

confidence: 99%

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Disassembly of Faceted Macrosteps in the Step Droplet Zone in Non-Equilibrium Steady State

Akutsu¹

2017

Crystals

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“…Hence, the steps are self-pinned by the locally formed merged steps without adsorbates, impurities, or dislocations. 17,18 Recently, this self-pinning of steps has been observed experimentally, 24 and it has been found to degrade the quality of the resulting crystal.…”

Section: B Self-organization Of a Faceted Stepmentioning

confidence: 95%

“…1), and, in an ECS, a first-order shape transition occurs at the facet edge in the shape. [14][15][16][17][18] The inhibition of the crystal growth, due to the step-faceting near equilibrium, 17 has been observed experimentally, 24 and this inhibition degrades the quality of the crystal.…”

Section: Introductionmentioning

confidence: 93%

Faceting diagram for sticky steps

Akutsu

2016

AIP Advances

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Faceting diagrams for the step-faceting zone, the step droplet zone, and the GruberMullins-Pokrovsky-Talapov (GMPT) zone for a crystal surface are obtained by using the density matrix renormalization group method to calculate the surface tension. The model based on these calculations is the restricted solid-on-solid (RSOS) model with a point-contact-type step-step attraction (p-RSOS model) on a square lattice. The point-contact-type step-step attraction represents the energy gain obtained by forming a bonding state with orbital overlap at the meeting point of the neighboring steps. In the step-faceting zone, disconnectedness in the surface tension leads to the formation of a faceted macrostep on a vicinal surface at equilibrium. The disconnectedness in the surface tension also causes the first-order shape transition for the equilibrium shape of a crystal droplet. The lower zone boundary line (ZBL), which separates the step-faceting zone and the step droplet zone, is obtained by the condition γ 1 = lim n→ ∞ γ n /n, where γ n is the step tension of the n-th merged step. The upper ZBL, which separates the GMPT zone and the step droplet zone, is obtained by the condition A q,eff = 0 and B q,eff = 0, where A q,eff and B q,eff represent the coefficients for the |⃗ q| 2 term and the |⃗ q| 3 term, respectively, in the |⃗ q|-expanded form of the surface free energy f eff (⃗ q). Here, ⃗ q is the surface gradient relative to the (111) surface. The reason why the vicinal surface inclined in the ⟨101⟩ direction does not exhibit stepfaceting is explained in terms of the one-dimensional spinless quasi-impenetrable attractive bosons at absolute zero. C 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license

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Optimization of Flow Distribution by Topological Description and Machine Learning in Solution Growth of SiC

Isono

Harada

Kutsukake

et al. 2022

Advcd Theory and Sims

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The macroscopic distribution of fluid flows, which affect the quality of final products for various kinds of materials, is often difficult to describe in mathematical formulae and hinders the implementation of empirical knowledge in scaling up. In the present study, the characteristics of the flow distribution in silicon carbide (SiC) solution growth are described by using the position of the saddle point and the solution growth conditions are optimized by computational fluid dynamics simulation, machine learning, and a genetic algorithm. As a result, the candidates of the optimal condition for the solution growth of 6-in. SiC crystals are successfully obtained from the empirical knowledge gained from 3-in. crystal growth, by adding the topological description to the objective function. The present design of the objective function using the topological description can possibly be applied to other crystal growth or materials processing problems and to overcome scale-up difficulties, which can facilitate the rapid development of functional materials such as SiC wafers for power device applications. . IntroductionFluid flow that arises in many materials processing techniques, such as crystal growth, casting, thin film fabrication, and polymer processing, is critical to the quality and characteristics of the final product and optimization of the system. [1] Recent advances in computational fluid dynamics (CFD) aid in the design of suitable conditions for materials processing. [2] Furthermore, the

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Effect of aluminum addition on the surface step morphology of 4H–SiC grown from Si–Cr–C solution

Cited by 51 publications

References 27 publications

Disassembly of Faceted Macrosteps in the Step Droplet Zone in Non-Equilibrium Steady State

Disassembly of Faceted Macrosteps in the Step Droplet Zone in Non-Equilibrium Steady State

Faceting diagram for sticky steps

Optimization of Flow Distribution by Topological Description and Machine Learning in Solution Growth of SiC

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