In situ investigation of the destabilisation of the solid–liquid interface during solidification in pure silicon and in intentionally copper-contaminated silicon
Abstract
The morphology of the solid-liquid interface during silicon solidification plays a critical role in determining the defect formation that ultimately affects the performance of photovoltaic materials. In this study, the destabilisation mechanisms of the solid-liquid interface during directional solidification of both nominally pure and intentionally copper (Cu)-contaminated silicon are investigated through in situ and time-resolved observations. Experiments are performed using optical microscopy and synchrotron X-ray radiography to monitor interface evolution under controlled temperature gradients and cooling conditions. Complementary ex situ electron backscatter diffraction (EBSD) analyses are conducted to characterize the resulting grain structures. In pure silicon samples, the interface morphology evolves progressively with increasing growth velocity from smooth to wavy, zig-zagged and then facetted. This transition is associated with kinetic effects and local temperature gradient modifications induced by latent heat release near the interface. In contrast, Cu-contaminated samples exhibit earlier interface destabilisation driven by constitutional undercooling resulting from impurity segregation ahead of the growth front. Higher Cu concentrations significantly reduce the critical velocity required for instabilities to develop and promote extensive dendritic growth. The formation of the resulting grain structure is also discussed. It is shown that the presence of Cu enhances grain nucleation. These results highlight the combined influence of thermal conditions and impurity segregation on interface stability during silicon crystal growth. Improved control of growth parameters and impurity levels are essential for minimizing defect formation.
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BibTeX
@article{houam2026situ,
title = {{In situ investigation of the destabilisation of the solid–liquid interface during solidification in pure silicon and in intentionally copper-contaminated silicon}},
author = {Sirine Houam and Lu Chung Chuang and Kozo Fujiwara and Gabrielle Regula and Guillaume Reinhart and Isabelle Périchaud and Fabrice Guittonneau and Laurent Barrallier and Nathalie Mangelinck-Noël},
journal = {Journal of Crystal Growth},
year = {2026},
month = oct,
doi = {10.1016/j.jcrysgro.2026.128872},
url = {https://hal.science/hal-05800002v1},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - In situ investigation of the destabilisation of the solid–liquid interface during solidification in pure silicon and in intentionally copper-contaminated silicon
AU - Sirine Houam
AU - Lu Chung Chuang
AU - Kozo Fujiwara
AU - Gabrielle Regula
AU - Guillaume Reinhart
AU - Isabelle Périchaud
AU - Fabrice Guittonneau
AU - Laurent Barrallier
AU - Nathalie Mangelinck-Noël
PY - 2026
DA - 2026/10/08
JO - Journal of Crystal Growth
DO - 10.1016/j.jcrysgro.2026.128872
UR - https://hal.science/hal-05800002v1
AB - The morphology of the solid-liquid interface during silicon solidification plays a critical role in determining the defect formation that ultimately affects the performance of photovoltaic materials. In this study, the destabilisation mechanisms of the solid-liquid interface during directional solidification of both nominally pure and intentionally copper (Cu)-contaminated silicon are investigated through in situ and time-resolved observations. Experiments are performed using optical microscopy and synchrotron X-ray radiography to monitor interface evolution under controlled temperature gradients and cooling conditions. Complementary ex situ electron backscatter diffraction (EBSD) analyses are conducted to characterize the resulting grain structures. In pure silicon samples, the interface morphology evolves progressively with increasing growth velocity from smooth to wavy, zig-zagged and then facetted. This transition is associated with kinetic effects and local temperature gradient modifications induced by latent heat release near the interface. In contrast, Cu-contaminated samples exhibit earlier interface destabilisation driven by constitutional undercooling resulting from impurity segregation ahead of the growth front. Higher Cu concentrations significantly reduce the critical velocity required for instabilities to develop and promote extensive dendritic growth. The formation of the resulting grain structure is also discussed. It is shown that the presence of Cu enhances grain nucleation. These results highlight the combined influence of thermal conditions and impurity segregation on interface stability during silicon crystal growth. Improved control of growth parameters and impurity levels are essential for minimizing defect formation.
SN - 0022-0248
ER -