Reduction of Carbon and Oxygen Impurities in mc-Silicon Ingot Using Molybdenum Gas Shield in Directional Solidification Process

Kumar, M. Avinash; Srinivasan, M.; Ramasamy, P.

doi:10.1007/s12633-020-00775-w

Cited by 8 publications

(4 citation statements)

References 25 publications

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“…Finally, they all are segregated in the crystal through the melt. [21,[45][46][47][48][49][50] Melt-Crucible Interface:…”

Section: Chemical Reactionsmentioning

confidence: 99%

A Critical Review of The Process and Challenges of Silicon Crystal Growth for Photovoltaic Applications

Sekar,

Thamotharan,

Manickam

et al. 2023

Cryst. Res. Technol.

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Crystalline silicon (c‐Si) solar cells have been accepted as the only environmentally and economically acceptable alternative source to fossil fuels. The majority of commercially available solar cells of all Photovoltaic (PV) cells produced worldwide, are made of crystalline silicon. Due to their excellent price/performance ratio and their demonstrated ecological durability, crystalline silicon wafers are by far the most common absorber material used in the production of solar cells and modules today. These wafers are primarily made using either a directional solidification that produces large‐grained multi‐crystalline (mc‐Si) wafers with a greater defect density or a solar‐optimized Czochralski (Cz) growing method that produces crystalline silicon with low defect density (c‐Si). The grown crystalline wafer contains foreign atoms that enhance the wire saw damage, reduce the minority carrier lifetime as a result get the minimum conversion efficiency of the solar cells. The current review illustrates how the elements of the furnace system affect impurity production and distribution of the developed silicon ingot and how the growth process affects the chemical reaction. Additionally, it covers the outcomes of simulations and experiments conducted on the growing process of c‐Si and mc‐Si ingots and recommends the most appropriate processing parameters, geometrical system, and argon gas flow rate.

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“…Finally, they all are segregated in the crystal through the melt. [21,[45][46][47][48][49][50] Melt-Crucible Interface:…”

Section: Chemical Reactionsmentioning

confidence: 99%

A Critical Review of The Process and Challenges of Silicon Crystal Growth for Photovoltaic Applications

Sekar,

Thamotharan,

Manickam

et al. 2023

Cryst. Res. Technol.

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“…Crystals 2021, 11, x FOR PEER REVIEW 2 of 11 heaters [10,11], crucible cover [12][13][14] and heat exchanger block [15], to control the gas flow and pathway of impurity transport. The latter technique mainly focuses on modifying furnace pressure [16][17][18], gas flow rate [16,19] and growth rate [20], which is a more efficient and easier way to operate for producing high purity silicon ingots in industrial production.…”

Section: Model Descriptionmentioning

confidence: 99%

“…Considerable research has been carried out to control the oxygen and carbon concentrations and transport during the DS process, such as hot-zone design of furnace and optimization of operating parameters. The former method is dedicated to the configuration or the material of the local components, such as gas flow guidance device [5][6][7][8][9], graphite heaters [10,11], crucible cover [12][13][14] and heat exchanger block [15], to control Crystals 2021, 11, 421 2 of 11 the gas flow and pathway of impurity transport. The latter technique mainly focuses on modifying furnace pressure [16][17][18], gas flow rate [16,19] and growth rate [20], which is a more efficient and easier way to operate for producing high purity silicon ingots in industrial production.…”

Section: Introductionmentioning

confidence: 99%

Effect of Argon Flow on Oxygen and Carbon Coupled Transport in an Industrial Directional Solidification Furnace for Crystalline Silicon Ingots

Xue

et al. 2021

Crystals

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Transient global simulations were carried out to investigate the effect of argon flow on oxygen and carbon coupled transport in an industrial directional solidification furnace for quasi-single crystalline silicon ingots. Global calculation of impurity transport in the argon gas and silicon melt was based on a fully coupled calculation of the thermal and flow fields. Numerical results show that the argon flow rate affects the flow intensity along the melt–gas surface, but has no significant effect on the flow patterns of silicon melt and argon gas above the melt–gas surface. It was found that the evaporation flux of SiO along the melt–gas surface decreases with the increasing argon flow rate during the solidification process. However, the net flux of oxygen atoms (SiO evaporation flux minus CO dissolution flux) away from the melt–gas surface increases with the increasing argon flow rate, leading to a decrease in the oxygen concentration in the grown ingot. The carbon concentration in the grown ingot shows an exponential decrease with the increase of the argon flow rate, owing to the fact that the dissolution flux of CO significantly decreases with the increasing argon flow rate. The numerical results agree well with the experimental measurements.

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“…Another important method that cannot be ignored is to decrease the impurity concentration by controlling the transport path of O and C, for example, by increasing furnace pressure [12,13], or increasing the gas flow rate [2,14]. A lot of effort and attempts were also made in furnace structure design and optimization, including the modification and optimization of the cover [15][16][17], the improvement of the graphite heater [18,19], the design of an argon gas guidance structure [20][21][22], etc. However, some of this research neglected the O and C transport in the silicon melt or did not consider the segregation of O and C during the casting of the silicon.…”

Section: Introductionmentioning

confidence: 99%

Design and Numerical Study of Argon Gas Diversion System Using Orthogonal Experiment to Reduce Impurities in Large-Sized Casting Silicon

Zhang

et al. 2022

Crystals

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To reduce oxygen and carbon impurities while casting silicon, an argon gas diversion system is proposed. A series of two-dimensional global transient numerical simulations are carried out using Fluent software according to the orthogonal experimental design, including heat transfer, convection of silicon melt and argon gas, and the fully coupling transport of impurities. The numerical results show that when the distance between the outer tube outlet and the cover is 10 mm, the backflow is inhibited by lateral outflow, thus the generation of CO is suppressed and the penetration of impurities into the silicon melt is decreased. The larger the flow rate, the more obvious the effect is. When the outer tube outlet is far from the cover, the effect of removing impurities is no longer significant. In addition, too large or too small an inner tube flow rate is not conducive to impurity reduction. The optimal parameter combination of outer tube flow rate, inner tube flow rate, and the distance between outer tube outlet and the cover are determined by the orthogonal experiment. Compared with the original furnace, the average concentration of oxygen and carbon in casting silicon ingots could be decreased by 7.4% and 59.9%, respectively, by using the optimized argon gas diversion system.

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Reduction of Carbon and Oxygen Impurities in mc-Silicon Ingot Using Molybdenum Gas Shield in Directional Solidification Process

Cited by 8 publications

References 25 publications

A Critical Review of The Process and Challenges of Silicon Crystal Growth for Photovoltaic Applications

A Critical Review of The Process and Challenges of Silicon Crystal Growth for Photovoltaic Applications

Effect of Argon Flow on Oxygen and Carbon Coupled Transport in an Industrial Directional Solidification Furnace for Crystalline Silicon Ingots

Design and Numerical Study of Argon Gas Diversion System Using Orthogonal Experiment to Reduce Impurities in Large-Sized Casting Silicon

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