CVD SiC Powder for High-Purity SiC Source Material

Ezaki, Sashiro; Saito, Mitsuhiro; Ishino, Kenei

doi:10.4028/www.scientific.net/msf.389-393.155

Cited by 3 publications

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“…Meanwhile, SiC is a significant reactant for the production of silicon ,. The concentration of B and P in SiC can be controlled under 0.1 ppmw, which meets the required level for solar cells. Herein, high‐purity SiC is proposed as the reducing agent.…”

Section: Introductionmentioning

confidence: 88%

Clean Synthesis and Formation Mechanisms of High‐Purity Silicon for Solar Cells by the Carbothermic Reduction of SiC with SiO₂

et al. 2019

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Metallurgical synthesis of solar grade silicon (SoGÀ Si) is an existing challenge due to the strict chemical composition of silicon for solar cells. Here, we report a green and facile approach to synthesize high-purity silicon (99.98 wt%, 0.12 ppmw B and 0.18 ppmw P) for solar cells by the carbothermic reduction of SiC with SiO 2 in a vacuum graphite resistance furnace. Catalyst of Fe 2 O 3 plays the role of reducing the concentration of CO (g) , lowering the energy consumption and improving the purity and yield of silicon. The present work is one-step to obtain silicon with less B and P, but it is composed of silicon synthesis, oxidation refining, vacuum refining and blowing refining, which discloses an innovative chemical concepts of in-situ synthesis combined with refining. According to the characterizations of the reacted SiC particles performed by XRD, Raman, PL, XPS, SEM and TEM, the morphologies and formation mechanisms of the in-situ silicon from the horizons of atomic scale were revealed for the first time. It was evidenced conclusively that the SiÀ C bonding is broken from the (006) planes of 6H-SiC at 1850°C by the reaction of SiC (s) + 2SiO 2(l) = 3SiO (g) + CO (g) , and then the silicon nucleates on the (101) planes of 6H-SiC and grows along the [111] direction at 1950°C via the vapor-solid reaction of SiO (g) + SiC (s) = 2Si (l) + CO (g) .High-purity SiO 2 (low content of B and P) can be achieved relatively easily, whereas it is difficult for carbon materials. Herein, it is urgent to use a high-purity reducing agent. [23,24] In fact, the actual reduction process of reaction (1) is much more complicated, which includes the formation of intermediate species, such as SiO (g) and SiC. Meanwhile, SiC is a significant reactant for the production of silicon. [25,26] The concentration of B and P in SiC can be controlled under 0.1 ppmw, [27] which meets the required level for solar cells. Herein, high-purity SiC is proposed as the reducing agent.

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Section: Introductionmentioning

confidence: 88%

Clean Synthesis and Formation Mechanisms of High‐Purity Silicon for Solar Cells by the Carbothermic Reduction of SiC with SiO₂

et al. 2019

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“…The step height between covered and uncovered areas approximately corresponded to the depth of aluminum contamination. Although the origin of aluminum is not cleared, we consider that the aluminum came from crucible (aluminum concentration was about 0.1ppm [5]). We consider the origin of increase of leakage current as below.…”

Section: Resultsmentioning

confidence: 99%

Suppression of Leakage Current Increase of 4H-SiC Schottky Barrier Diodes during High-Temperature Annealing by "Face-to-Face" Arrangement

Izumi

Fujisawa

Tawara

et al. 2003

MSF

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Ni/4H-SiC Schottky barrier diodes (SBDs) were fabricated by using "face-to-face" annealing technique. As a result, we can obtain the SBDs with low leakage current in the covered area of the bottom chip reproducibly. The leakage current of this area is comparable to that of the samples without annealing. We found that the surface of this area was etched during annealing, and the increase in surface roughness was suppressed.

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“…The SiC powder prepared by Acheson's method is generally used as a source material for the sublimation method. Since the powder cannot be purified by other than washing with acid or by some similar treatment, there is a limit to the purity [3]. We have studied the 6H-SiC bulk growth by sublimation method earlier [4,5].…”

Section: Introductionmentioning

confidence: 99%

High Quality SiC Bulk Growth by Sublimation Method using Elemental Silicon and Carbon Powder as SiC Source Materials

Ota

Furusho²,

Takagi

et al. 2004

MSF

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The growth of 6H-SiC bulk by physical vapor transport (PVT) method using elemental silicon (Si) and carbon (C) powder as source materials has been investigated. To investigate the optical and electrical characteristics of bulk crystals, the C/Si ratio of source materials was varied. The properties of bulk crystals, obtained by this method were compared with crystals grown using SiC powder that was used for abrasive purposes. By using elemental Si and C, the purity of the bulk crystal was improved with a resistivity of 3 x 10 6 Ω-cm.

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CVD SiC Powder for High-Purity SiC Source Material

Cited by 3 publications

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Clean Synthesis and Formation Mechanisms of High‐Purity Silicon for Solar Cells by the Carbothermic Reduction of SiC with SiO₂

Clean Synthesis and Formation Mechanisms of High‐Purity Silicon for Solar Cells by the Carbothermic Reduction of SiC with SiO₂

Suppression of Leakage Current Increase of 4H-SiC Schottky Barrier Diodes during High-Temperature Annealing by "Face-to-Face" Arrangement

High Quality SiC Bulk Growth by Sublimation Method using Elemental Silicon and Carbon Powder as SiC Source Materials

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CVD SiC Powder for High-Purity SiC Source Material

Cited by 3 publications

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Clean Synthesis and Formation Mechanisms of High‐Purity Silicon for Solar Cells by the Carbothermic Reduction of SiC with SiO2

Clean Synthesis and Formation Mechanisms of High‐Purity Silicon for Solar Cells by the Carbothermic Reduction of SiC with SiO2

Suppression of Leakage Current Increase of 4H-SiC Schottky Barrier Diodes during High-Temperature Annealing by "Face-to-Face" Arrangement

High Quality SiC Bulk Growth by Sublimation Method using Elemental Silicon and Carbon Powder as SiC Source Materials

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Clean Synthesis and Formation Mechanisms of High‐Purity Silicon for Solar Cells by the Carbothermic Reduction of SiC with SiO₂

Clean Synthesis and Formation Mechanisms of High‐Purity Silicon for Solar Cells by the Carbothermic Reduction of SiC with SiO₂