In Situ Imaging of Dislocation Expansion in FZ‐Si Seeds During Temperature Ramp Heating Process

Tsoutsouva, M.G.; Riberi-Béridot, Thècle; Regula, G.; Reinhart, Gunther; Baruchel, J.; Mangelinck‐Noël, Nathalie

doi:10.1002/pssa.201700758

Cited by 6 publications

(12 citation statements)

References 22 publications

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“…During the heating segment of the experimental procedure, dislocations appear in the sample as seen before [36] and remain in the seed kept after partial melting. During solidification, these dislocations develop, usually along the growth direction and can encounter grain boundaries.…”

Section: Grain Competition and Associated Strain Buildingmentioning

confidence: 99%

Strain building and correlation with grain nucleation during silicon growth

et al. 2019

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This work is dedicated to the grain structure formation in silicon ingots with a particular focus on the crystal structure strain building and its implication in new grain nucleation process. The implied mechanisms are investigated by advanced in situ X-ray imaging techniques during silicon directional solidification. It is shown that the grain structure formation is mainly driven by Σ3 <111> twin nucleation. Grain competition phenomena occurring during the growth process lead to the creation of higher order twin boundaries, localised strained areas and associated crystal structure deformation. On the one hand, it is demonstrated that local strain building can be directly related to the characteristics of the twin boundaries created during silicon growth due to grain competition. On the other hand, space restriction due to competition during growth can be at the origin of local strain building as well. Finally, the accumulation of all these factors generating strain is responsible for spontaneous new grain nucleation. When occurring, both grain nucleation and subsequent grain structure reorganisation contribute to lower the strain in the growing ingot.It is demonstrated as well that the local distribution of the strained areas created during silicon growth is retrieved after cooling down, from melting temperature to room temperature, on top of an additional larger scale deformation of the sample due to the cooling down only.

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Section: Grain Competition and Associated Strain Buildingmentioning

confidence: 99%

Strain building and correlation with grain nucleation during silicon growth

et al. 2019

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“…It was shown by Tsoutsouva et al (2018) that at a temperature of 1373 K a horizontal slip system is activated for a sample of the same orientation as sample B and with the same crucible arrangement and comparable temperature conditions. It was concluded that this slip system initiates from the sample side zones that are damaged during preparation and is activated by an external force acting on the sample surface, i.e.…”

Section: Heating and Meltingmentioning

confidence: 99%

Simultaneous X-ray radiography and diffraction topography imaging applied to silicon for defect analysis during melting and crystallization

Becker¹,

Regula²,

Reinhart³

et al. 2019

J Appl Cryst

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One of the key issues to be resolved to improve the performance of silicon solar cells is to reduce crystalline defect formation and propagation during the growth‐process fabrication step. For this purpose, the generation of structural defects such as grain boundaries and dislocations in silicon must be understood and characterized. Here, in situ X‐ray diffraction imaging, historically named topography, is combined with radiography imaging to analyse the development of crystal defects before, during and after crystallization. Two individual indirect detector systems are implemented to record simultaneously the crystal structure (topographs) and the solid–liquid morphology evolution (radiographs) at high temperature. This allows for a complete synchronization of the images and for an increased image acquisition rate compared with previous studies that used X‐ray sensitive films to record the topographs. The experiments are performed with X‐ray synchrotron radiation at beamline ID19 at the European Synchrotron Radiation Facility. In situ observations of the heating, melting, solidification and holding stages of silicon samples are presented, to demonstrate that with the upgraded setup detailed investigations of time‐dependent phenomena are now possible. The motion of dislocations is recorded throughout the experiment, so that their interaction with grain boundaries and their multiplication through the activation of Frank–Read sources can be observed. Moreover, the capability to record with two camera‐based detectors allows for the study of the relationship between strain distribution, twinning and nucleation events. In conclusion, the simultaneous recording of topographs and radiographs has great potential for further detailed investigations of the interaction and generation of grains and defects that influence the growth process and the final crystalline structure in silicon and other crystalline materials.

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“…Another main originality of the experimental configuration we use is that several Laue patterns or topographs are recorded during a solidification experiment [45,46,71]. Then, it is possible to obtain sequences showing the evolution with time of the Laue pattern and of the topographs during the development of the grains.…”

Section: Dynamic Evolutionmentioning

confidence: 99%

“…Before presenting results on strain building, it is important to specify that during the heating segment of the experimental procedure, dislocations appear in the sample as described in [71] and remain in the seed kept after partial melting. During solidification, these dislocations develop, usually along the growth direction and can encounter grain boundaries.…”

Section: Strain Building During Growthmentioning

confidence: 99%

X-ray Based in Situ Investigation of Silicon Growth Mechanism Dynamics—Application to Grain and Defect Formation

et al. 2020

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To control the final grain structure and the density of structural crystalline defects in silicon (Si) ingots is still a main issue for Si used in photovoltaic solar cells. It concerns both innovative and conventional fabrication processes. Due to the dynamic essence of the phenomena and to the coupling of mechanisms at different scales, the post-mortem study of the solidified ingots gives limited results. In the past years, we developed an original system named GaTSBI for Growth at high Temperature observed by Synchrotron Beam Imaging, to investigate in situ the mechanisms involved during solidification. X-ray radiography and X-ray Bragg diffraction imaging (topography) are combined and implemented together with the running of a high temperature (up to 2073 K) solidification furnace. The experiments are conducted at the European Synchrotron Radiation Facility (ESRF). Both imaging techniques provide in situ and real time information during growth on the morphology and kinetics of the solid/liquid (S/L) interface, as well as on the deformation of the crystal structure and on the dynamics of structural defects including dislocations. Essential features of twinning, grain nucleation, competition, strain building, and dislocations during Si solidification are characterized and allow a deeper understanding of the fundamental mechanisms of its growth.

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In Situ Imaging of Dislocation Expansion in FZ‐Si Seeds During Temperature Ramp Heating Process

Cited by 6 publications

References 22 publications

Strain building and correlation with grain nucleation during silicon growth

Strain building and correlation with grain nucleation during silicon growth

Simultaneous X-ray radiography and diffraction topography imaging applied to silicon for defect analysis during melting and crystallization

X-ray Based in Situ Investigation of Silicon Growth Mechanism Dynamics—Application to Grain and Defect Formation

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