Simultaneous X-ray radiography and diffraction topography imaging applied to silicon for defect analysis during melting and crystallization
Simultaneous X-ray radiography and diffraction topography imaging applied to silicon for defect analysis during melting and crystallization
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DOI：
10.1107/s1600576719013050
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发表时间：
2019-12-01
影响因子：
6.1
通讯作者：
Mangelinck-Noel, Nathalie
中科院分区：
文献类型：
--
作者：
Becker, Maike;Regula, Gabrielle;Mangelinck-Noel, Nathalie
提高硅太阳电池性能需要解决的关键问题之一是减少生长过程中晶体缺陷的形成和扩展。为此，必须了解和表征硅中晶界和位错等结构缺陷的产生。在这里，原位X射线衍射成像，历史上被称为形貌术，结合射线成像，分析晶体缺陷在结晶前、结晶中和结晶后的发展。实现了两个独立的间接探测器系统，以同时记录高温下的晶体结构(形貌)和固-液形态演变(射线照片)。与以前使用X射线感光胶片记录地形的研究相比，这允许完全同步图像并提高图像采集率。这些实验是在欧洲同步辐射设施的ID19光束线上用X射线同步辐射进行的。给出了对硅样品的加热、熔化、凝固和保持阶段的现场观测，以证明通过改进的装置，现在可以对随时间变化的现象进行详细的研究。在整个实验过程中记录了位错的运动，从而可以观察到它们与晶界的相互作用以及它们通过激活Frank-Read源而增殖。此外，使用两个基于相机的探测器进行记录的能力允许研究应变分布、孪生和形核事件之间的关系。总之，同时记录形貌和射线照片对于进一步详细研究影响硅和其他晶体材料的生长过程和最终晶体结构的颗粒和缺陷的相互作用和产生具有很大的潜力。
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.