Deformation and recrystallization textures in compressed polycrystalline silicon

Pratt, B.; Kulkarni, Sneha A.; Pope, D. P.; Graham, C. D.; Noel, G. T.

doi:10.1007/bf02646885

Cited by 10 publications

(6 citation statements)

References 2 publications

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“…Similar behavior has been observed for other fcc metals. [20][21][22] Tsuji et al [21] suggested that grains in ferritic and austentic steels with their {100} poles oriented parallel to the compression axis are more difficult to recrystallize, so the h100i fiber texture is a result of the remaining deformed grains that have not yet recrystallized. [21] However, the microstructure containing this texture in INCOLOY 945 is 94 pct recrystallized; the nonrecrystallized grains therefore have marginal contribution to the observed texture.…”

Section: Texture Developmentmentioning

confidence: 99%

Evolution of Microstructure and Texture During Hot Compression of a Ni-Fe-Cr Superalloy

Coryell¹,

Findley

Mataya

et al. 2011

Metall Mater Trans A

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Superalloys are being employed in more extreme conditions requiring higher strength, which requires producers to forge products to finer grain sizes with less grain size variability. To assess grain size, crystallographic texture, and substructure as a function of forging conditions, frictionless uniaxial compression testing characteristic of hot working was performed on INCOLOY 945 (Special Metals Corporation, Huntington, WV), which is a newly developed hybrid of alloys 718 and 925, over a range of temperatures and strain rates. The microstructure and texture were investigated comprehensively using light optical microscopy, electron backscatter diffraction (EBSD), electron channeling contrast imaging (ECCI), and transmission electron microscopy (TEM) to provide detailed insight into microstructure evolution mechanisms. Dynamic recrystallization, nucleated by grain/twin boundary bulging with occasional subgrain rotation, was found to be a dominant mechanism for grain refinement in INCOLOY 945. At higher strain rates, static recrystallization occurred by grain boundary migration. During deformation, duplex slip along {111} planes occurred until a stable h110i fiber compression texture was established. Recrystallization textures were mostly random but shifted toward the compression texture with subsequent deformation. An exception occurred at 1423 K (1150°C) and 0.001 seconds À1 , the condition with the largest fraction of recrystallized grains, where a h100i fiber texture developed, which may be indicative of preferential growth of specific grain orientations.

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Section: Texture Developmentmentioning

confidence: 99%

Evolution of Microstructure and Texture During Hot Compression of a Ni-Fe-Cr Superalloy

Coryell¹,

Findley

Mataya

et al. 2011

Metall Mater Trans A

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“…The deformation and subsequent annealing of bulk polysilicon were studied by previous researchers under different conditions . Recrystallization in both cast and CVD grown polycrystalline silicon after high temperature plastic deformation and subsequenting annealing has been widely observed, and this is analogous to the behavior of metals.…”

Section: Discussionmentioning

confidence: 99%

“…Kulkarni and Graham et al carried out plastic compression on CVD polysilicon at 1380 °C with various strain rates both along and normal to the original <110> fiber orientation . Their deformed polysilicon completed the recrystallization process after annealing at 1380 °C for 10 min when the sample was compressed perpendicular to the original <110> direction by 30% at 1380 °C.…”

Section: Discussionmentioning

confidence: 99%

“…An alternative method for rapid and cost‐effective silicon sheet fabrication is via hot mechanical rolling. Hot deformation of silicon was attempted in the late 1970s and early 1980s, and was found to be promising from a mechanical perspective . Polycrystalline silicon can be uniaxially compressed by as much as 50% at 1380 °C at a strain rate of 7 s −1 without cracking .…”

Section: Introductionmentioning

confidence: 99%

“…Our compression set‐up operates under clean conditions. As earlier deformation studies were carried out in metallurgical conditions with no apparent attempt to prevent contamination, we hope that our approach when combined with modern gettering and passivation processes will eventually result in wafers with adequate electronic properties.…”

Section: Introductionmentioning

confidence: 99%

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Microstructural Evolution of Mechanically Deformed Polycrystalline Silicon for Kerfless Photovoltaics

Murphy

Jiang

et al. 2018

Physica Status Solidi (a)

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Silicon wafers for photovoltaics could be produced without kerf loss by rolling, provided sufficient control of defects such as dislocations can be achieved. A study using mainly high resolution electron backscatter diffraction (HR‐EBSD) of the microstructural evolution of Siemens polycrystalline silicon feedstock during a series of processes designed to mimic high temperature rolling is reported here. The starting material is heavily textured and annealing at 1400 °C results in 90% recrystallization and a reduction in average geometrically necessary dislocation (GND) density from >1014 to 1013 m−2. Subsequent compression at 1150 °C – analogous to rolling – produce sub‐grain boundaries seen as continuous curved high GND content linear features spanning grain interiors. Post‐deformation annealing at 1400 °C facilitates a secondary recrystallization process, resulting in large grains typically of 100 μm diameter. HR‐EBSD gives the final average GND density in as 3.2 × 1012 m−2. This value is considerably higher than the dislocation density of 5 × 1010 m−2 from etch pit counting, so the discrepancy is investigated by direct comparison of GND maps and etch pit patterns. The GND map from HR‐EBSD gives erroneously high values at the method's noise floor (≈1012 m−2) in regions with low dislocation densities.

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Deformation and recrystallization of polycrystalline silicon

Schins

Radelaar

1981

J Mater Sci

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Deformation and recrystallization textures in compressed polycrystalline silicon

Cited by 10 publications

References 2 publications

Evolution of Microstructure and Texture During Hot Compression of a Ni-Fe-Cr Superalloy

Evolution of Microstructure and Texture During Hot Compression of a Ni-Fe-Cr Superalloy

Microstructural Evolution of Mechanically Deformed Polycrystalline Silicon for Kerfless Photovoltaics

Deformation and recrystallization of polycrystalline silicon

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