https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Fri, 05 Jun 2026 23:09:57 GMT 2026-06-05T23:09:57Z http://hdl.handle.net/10985/18495 In situ investigation of the structural defect generation and evolution during the directional solidification of 〈110〉 seeded growth Si TSOUTSOUVA, M.G.; RIBERI – BÉRIDOT, T.; REGULA, G.; REINHART, G.; BARUCHEL, José; GUITTONNEAU, Fabrice; MANGELINCK-NOËL, N.; BARRALLIER, Laurent This work is dedicated to the advanced in situ X-ray imaging and complementary ex situ investigations of the growth mechanisms when silicon solidifies on a monocrystalline seed oriented ⟨110⟩ in the solidification direction. It aims at deepening the fundamental understanding of the phenomena that occur throughout silicon crystal growth with a particular focus on mechanisms of formation of defects detrimental for photovoltaic applications. Namely, grain nucleation, grain boundary formation and evolution, grain competition, twining occurrence, dislocation generation and interaction with structural defects are explored and analysed. Nucleation of twin crystals preferentially occurs on {111} facets at the edge of the sample where solid e liquid e vapor triple point lines exist in interaction also with the crucible as well as, at grain boundary grooves at the solid e liquid interface (solid e solid e liquid triple lines), where two grains are in competition, either on the {111} facets of the groove or in the groove. Enhanced undercooling and/or stress accumulation levels are found to act as driving forces for grain nucleation. Additionally, it is demonstrated that twin formation has the property to relax stresses stored in the crystal during the growth process. However, grains formed initially in twin position can undergo severe distortion when they are in direct competition or when they are squeezed in e between grains. Moreover, we show by X-ray Bragg diffraction imaging that on the one hand, coherent S3 ⟨111⟩ grain boundaries efficiently block the propagation of growth dislocations during the solidification process, while on the other hand, dislocations are emitted at the level of incoherent and/or asymmetric S27a ⟨110⟩ at the encounter with either S3 ⟨111⟩ or S9 ⟨110⟩ grain boundaries. Indeed, grain boundaries that deviate from the ideal coincidence orientation act as dislocation sources that spread inside the surrounding crystals. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10985/18495 2016-01-01T00:00:00Z TSOUTSOUVA, M.G. RIBERI – BÉRIDOT, T. REGULA, G. REINHART, G. BARUCHEL, José GUITTONNEAU, Fabrice MANGELINCK-NOËL, N. BARRALLIER, Laurent This work is dedicated to the advanced in situ X-ray imaging and complementary ex situ investigations of the growth mechanisms when silicon solidifies on a monocrystalline seed oriented ⟨110⟩ in the solidification direction. It aims at deepening the fundamental understanding of the phenomena that occur throughout silicon crystal growth with a particular focus on mechanisms of formation of defects detrimental for photovoltaic applications. Namely, grain nucleation, grain boundary formation and evolution, grain competition, twining occurrence, dislocation generation and interaction with structural defects are explored and analysed. Nucleation of twin crystals preferentially occurs on {111} facets at the edge of the sample where solid e liquid e vapor triple point lines exist in interaction also with the crucible as well as, at grain boundary grooves at the solid e liquid interface (solid e solid e liquid triple lines), where two grains are in competition, either on the {111} facets of the groove or in the groove. Enhanced undercooling and/or stress accumulation levels are found to act as driving forces for grain nucleation. Additionally, it is demonstrated that twin formation has the property to relax stresses stored in the crystal during the growth process. However, grains formed initially in twin position can undergo severe distortion when they are in direct competition or when they are squeezed in e between grains. Moreover, we show by X-ray Bragg diffraction imaging that on the one hand, coherent S3 ⟨111⟩ grain boundaries efficiently block the propagation of growth dislocations during the solidification process, while on the other hand, dislocations are emitted at the level of incoherent and/or asymmetric S27a ⟨110⟩ at the encounter with either S3 ⟨111⟩ or S9 ⟨110⟩ grain boundaries. Indeed, grain boundaries that deviate from the ideal coincidence orientation act as dislocation sources that spread inside the surrounding crystals. http://hdl.handle.net/10985/18496 Strain building and correlation with grain nucleation during silicon growth RIBERI – BÉRIDOT, T.; TSOUTSOUVA, M.G.; REGULA, G.; REINHART, G.; GUITTONNEAU, Fabrice; MANGELINCK-NOËL, N.; BARRALLIER, Laurent 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 S3 <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. Tue, 01 Jan 2019 00:00:00 GMT http://hdl.handle.net/10985/18496 2019-01-01T00:00:00Z RIBERI – BÉRIDOT, T. TSOUTSOUVA, M.G. REGULA, G. REINHART, G. GUITTONNEAU, Fabrice MANGELINCK-NOËL, N. BARRALLIER, Laurent 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 S3 <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.