A metallurgical route to produce upgraded silicon and monosilane

Mukashev, B.N.; Абдуллин, Х.А.; Tamendarov, M.F.; Turmagambetov, Tleuzhan; Beketov, B.A.; Page, Matthew; Kline, David

doi:10.1016/j.solmat.2009.06.011

Cited by 35 publications

(22 citation statements)

References 7 publications

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“…Thus, the boron reduction half-life is proportional to mass to the one-third power. In other words, if the reaction vessel diameter is doubled (and the charge size increased by 2 3 , or 8X) the effective boron reduction half-life would also be expected to double.…”

Section: Effect Of Molten Pool Size On Half-lifementioning

confidence: 99%

“…These have included electron beam melting [1], [2], alumothermic reactions [3], chemical and physical methods such as bubbling reactive gas mixtures through the molten silicon [4] and even the use of concentrated sunlight as a heat source to melt and refine the silicon [5]. Some of these processes have not yet demonstrated low enough final boron concentration to meet the ideal resistivity target, even though the initial boron reduction may be rapid.…”

Section: Introductionmentioning

confidence: 99%

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Efficacy of plasma arc treatment for the reduction of boron in the refining of solar-grade silicon

Imler¹,

Haun²,

Lampson³

et al. 2011

2011 37th IEEE Photovoltaic Specialists Conference

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Removal of boron is the major difficulty with refining metallurgical grade silicon into higher purity solar-grade silicon. A plasma arc refining process was developed which efficiently reduces the boron concentration in silicon to below 0.01 ppmW, enabling a low-cost process for manufacturing polysilicon comparable in quality to that made through the Siemens process. The low background boron concentration achieved allows deliberate tailoring of both n-type and p-type ingot resistivity.Silicon refining experiments were performed in a large general-purpose plasma arc melting system. A reaction vessel with independent heating and stirring capabilities was installed in the vacuum chamber, and a single argon plasma torch was used to drive the boron reduction reaction. Reactive gases such as hydrogen and oxygen were introduced to enhance boron removal.A simple half-life model, characterized by the time required to reduce the boron concentration to half its initial value, was particularly useful in comparing a wide range of silicon feedstock purity, different boron reduction processes and the effect of various process parameters on boron reduction. Implications of this model for equipment and process design will be discussed.The effects of several important process variables on the boron reduction half-life were quantitatively determined by experiment. Variables included melt temperature, gas phase chemistry and melt size. The boron reduction halflife was found to increase linearly with silicon melt temperature above the melting point, most likely due to increased silicon vapor pressure, preventing the reactive gas from reaching the molten silicon surface. Although some boron reduction was achieved by adding hydrogen to the chamber atmosphere, the presence of oxygen was found to be crucial in obtaining a short half-life. In general, boron reduction rates were found to be lower for larger melt and crucible sizes, although this is strongly affected by equipment design. BACKGROUND

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Section: Effect Of Molten Pool Size On Half-lifementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Efficacy of plasma arc treatment for the reduction of boron in the refining of solar-grade silicon

Imler¹,

Haun²,

Lampson³

et al. 2011

2011 37th IEEE Photovoltaic Specialists Conference

View full text Add to dashboard Cite

show abstract

“…However, long treatment duration and a complicated hazardous acid mixture discharge make it difficult to be employed in practical industrial applications. On the other hand, the metallurgical refining process, which has been attempted for the MG-Si purification (Supporting Information) [16,[22][23][24][25], is simple and well-established. The metallurgical refining process is also a promising method for purification of the EoL silicon wafers as the new resource for SoG-Si in new PV panels.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic criteria of the end-of-life silicon wafers refining for closing the recycling loop of photovoltaic panels

Miki

Takeda

et al. 2019

Science and Technology of Advanced Materials

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The collected end-of-life (EoL) silicon wafers from the discharged photovoltaic (PV) panels are easily contaminated by impurities such as doping elements and attached materials. In this study, the thermodynamic criteria for EoL silicon wafers refining using three most typical metallurgical refining processes: oxidation refining, evaporation refining, and solvent refining were systemically and quantitatively evaluated. A total of 42 elements (Ag,

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“…The production of silicon by the thermal reduction of silica with carbon is an industrial process used since the beginning of the 20 century [3,4,5]. The silicon produced using this method contains many undesirable impurities.…”

Section: Introductionmentioning

confidence: 99%

Quality Assessment of Sand as Silicon Dioxide Collected from the Sudanese Areas (Bara, Elmtama and Karema) for Glass Industry

Almaleeh¹,

Ezeldin²,

Milad³

2017

SJC

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Abstract:The silicon dioxide and microcline, samples were collected from the North Kordofan state Bara area, River Nile state Elmatama area and Karema. Then samples were subjected to X-ray diffractometer "XRD" accodrding to standard testMethods. Elemnts compostion was charactrized for all samples by X-ray florescence spectrometer "XRF". The particles size was carried out using sieve standards. Samples were acidified to improve the quality of silica. Silicon dioxide of Bara sand was found to be 100%, while that of Elmtama was 96.6% silicon dioxide and 3.4% microcline sandand for Karima sand 94% silicon dioxide and 6% microcline. The percentages of the silica sand were found to be 95.8% for Bara, 90.9% for Elmtama and 84.2% for karema. The iron oxide percentage for Bara was found 0.03%. The particle size for Bara, Karema and Elmtama were found to be (60, 100, 140mm), respectively.

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A metallurgical route to produce upgraded silicon and monosilane

Cited by 35 publications

References 7 publications

Efficacy of plasma arc treatment for the reduction of boron in the refining of solar-grade silicon

Efficacy of plasma arc treatment for the reduction of boron in the refining of solar-grade silicon

Thermodynamic criteria of the end-of-life silicon wafers refining for closing the recycling loop of photovoltaic panels

Quality Assessment of Sand as Silicon Dioxide Collected from the Sudanese Areas (Bara, Elmtama and Karema) for Glass Industry

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