Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8148617 | Journal of Crystal Growth | 2018 | 9 Pages |
Abstract
Besides the well-known local sub-grain boundaries (SGBs) defects, monolike Si ingots grown by Directional Solidification present distributed background cellular dislocation structures. In the present work, the influence of stress level, time under stress, and doping by O and Ge, on the formation of dislocation cells in monolike silicon, is analysed. This is achieved by performing a comparative study of the dislocation structures respectively obtained during crystallisation of pilot scale monolike ingots on Czochralski (CZ) and monolike seeds, during annealing of Float Zone (FZ), CZ, and 1â¯Ãâ¯1020â¯at/cm3 Ge-doped CZ (GCZ) samples, and during 4-point bending of FZ and GCZ samples at 1300â¯Â°C under resolved stresses of 0.3, 0.7 and 1.9â¯MPa during 1-20â¯h. Synchrotron X-ray White-beam Topography and Rocking Curve Imaging (RCI) are applied to visualize the dislocation arrangements and to quantify the spatial distribution of the associated lattice distortions. Annealed samples and samples bent under 0.3â¯MPa present dislocation structures corresponding to transient creep stages where dislocations generated from surface defects are propagating and multiplying in the bulk. The addition of the hardening element Ge is found to block the propagation of dislocations from these surface sources during the annealing test, and to retard dislocation multiplication during bending under 0.3â¯MPa. On the opposite, cellular structures corresponding to the final stationary creep stage are obtained both in the non-molten seeds and grown part of monolike ingots and in samples bent under 0.7 and 1.9â¯MPa. A comparative discussion is made of the dynamics of formation of these final dislocation structures during deformation at high temperature and monolike growth.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
V.A. Oliveira, M. Rocha, A. Lantreibecq, M.G. Tsoutsouva, T.N. Tran-Thi, J. Baruchel, D. Camel,