Influence of acrt on interface stability and particle trapping behavior in directional solidification of silicon

Ravishankar, P.S.; Dismukes, John P.; Wilcox, William R.

doi:10.1016/0022-0248(85)90364-1

Cited by 20 publications

(16 citation statements)

References 37 publications

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“…The carbon precipitation in solid is therefore neglected [15]. It has been reported [8] that the buoyancy-driven convection of melt flow in directional solidification of silicon is sufficient to keep small SiC particles suspended in the melt. It is therefore reasonable to assume that SiC particles are continuously distributed in the Si-melt and are mainly transported by melt convection.…”

Section: Sic Particle Precipitation Modelmentioning

confidence: 99%

See 1 more Smart Citation

Carbon concentration and particle precipitation during directional solidification of multicrystalline silicon for solar cells

Liu

Nakano

Kakimoto

2008

Journal of Crystal Growth

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Section: Sic Particle Precipitation Modelmentioning

confidence: 99%

“…Since MG-Si feedstock contains a higher level of impurities, it is important to study the characteristics of carbon segregation and SiC particle precipitation in a directional solidification process. Some experimental studies [2,[6][7][8] on these characteristics have been carried out.…”

Section: Introductionmentioning

confidence: 99%

Carbon concentration and particle precipitation during directional solidification of multicrystalline silicon for solar cells

Liu

Nakano

Kakimoto

2008

Journal of Crystal Growth

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“…In ingot-grown mc-Si, this corresponds to material near the edges of the crucible, as well as near the bottom and the top of the ingot. Incidentally, these regions are also where the majority of metal silicide precipitates are observed, suggesting that unstable crystal growth 22 and high metal concentrations dissolving from growth surfaces favor the formation of these nanodefects.…”

Section: On the Size And Distribution Of Inclusionsmentioning

confidence: 99%

“…12,13 It has become clear that in order to fully assess the effect of metals on solar cell performance, one must know not only the total concentrations of different metal species, but also about the spatial and size distributions of metal-related defects, [14][15][16] their chemical natures, [15][16][17] their interactions with different types of defects, [18][19][20][21] and their behavior 22,23 during the crystal growth process. In this study, we employ synchrotron-based analytical techniques to determine the aforementioned characteristics of metal contamination in a variety of mc-Si materials from multiple vendors.…”

Section: Introductionmentioning

confidence: 99%

Chemical natures and distributions of metal impurities in multicrystalline silicon materials

Buonassisi

Istratov

Pickett

et al. 2006

Progress in Photovoltaics

174

106

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We present a comprehensive summary of our observations of metal-rich particles in multicrystalline silicon (mc-Si) solar cell materials from multiple vendors, including directionally-solidified ingot-grown, sheet, and ribbon, as well as multicrystalline float zone materials contaminated during growth. In each material, the elemental nature, chemical states, and distributions of metal-rich particles are assessed by synchrotron-based analytical x-ray microprobe techniques. Certain universal physical principles appear to govern the behavior of metals in nearly all materials: (a) Two types of metal-rich particles can be observed (metal silicide nanoprecipitates and metal-rich inclusions up to tens of microns in size, frequently oxidized), (b) spatial distributions of individual elements strongly depend on their solubility and diffusivity, and (c) strong interactions exist between metals and certain types of structural defects. Differences in the distribution and elemental nature of metal contamination between different mc-Si materials can largely be explained by variations in crystal

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“…[1][2][3][4] There are many reports on the vertical and horizontal filmdrawing method [5][6][7] and the Czochralski method 8,9) for the manufacture technique of silicon for solar cell devices. 10) However, very few reports on the control of crystal orientation have been published, apart from some investigating the influences of convection 11) and impurities [12][13][14] on multicrystal silicon ingot processing. 15,16) To improve the quality of a multicrystal silicon ingot, it is necessary to remove impurities 3,17,18) and to clarify the mechanism by which the crystal grain grows to the appropriate size 19,20) because lattice defects and grain boundaries cause trapping of electrons and electron holes.…”

Section: Introductionmentioning

confidence: 99%

Effect of Twin Growth on Unidirectional Solidification Control of Multicrystal Silicon for Solar Cells

et al. 2005

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The solidification microstructure and crystal orientation have been investigated for solar cell grade high purity multicrystal silicon through a unidirectional solidification technique. The mechanism of the twin growth on a reentrant corner has been also discussed. A columnar structure is observed at solidification velocities of 1.25-30 mm/s and positive temperature gradient of 20 K/cm in the rod-like silicon specimens in an electric resistance furnace. In the solidification velocity range of 1.25-2.5 mm/s, the grain size enlarges as solidification progresses. Furthermore, large columnar grains contain many twin boundaries. However, the average grain size decreases as the solidification velocity increases and above the critical velocity around 40 mm/s, equiaxed structure appears at the central part of specimens. Therefore, molten silicon must be solidified at the velocity below 2.5 mm/s where twins are always introduced into grains to obtain large columnar crystal grains. The undercooling for directional growth is less than 4 K in the solidification velocity range of 1.25-30 mm/s. A model of two-dimensional nucleation on the reentrant corner was established, and the critical nucleus could be estimated to be 70 to 80% of the radius of the general two-dimensional nucleus. The nucleation undercooling on the surface containing twins also decreased to 70% of the general undercooling. The reduction of the critical radius and undercooling on the reentrant corner could eventually influence on the priority growth direction and the enlargement of the grain size.

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Influence of acrt on interface stability and particle trapping behavior in directional solidification of silicon

Cited by 20 publications

References 37 publications

Carbon concentration and particle precipitation during directional solidification of multicrystalline silicon for solar cells

Carbon concentration and particle precipitation during directional solidification of multicrystalline silicon for solar cells

Chemical natures and distributions of metal impurities in multicrystalline silicon materials

Effect of Twin Growth on Unidirectional Solidification Control of Multicrystal Silicon for Solar Cells

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