Grain boundaries and dislocations in Si-bricks: inline characterization on as-cut wafers. (September 2017)

• Record Type: Journal Article
• Authors: Strauch, Theresa; Demant, Matthias; Krenckel, Patricia; Riepe, Stephan; Rein, Stefan
• Is Part Of: Energy procedia. Volume 124(2017)
• Page Start: 806
• Page End: 813
• Publication Date: 2017-09
• Subjects: Dislocations -- Grain Boundaries -- Material Quality -- High-Performance mc-Si -- Image Processing; Power resources -- Congresses; Power resources -- Periodicals; Power resources; Conference proceedings; Periodicals; 333.7905
• DOI: 10.1016/j.egypro.2017.09.351
• Languages: English
• ISSNs: 1876-6102

Abstract

Abstract: In High-Performance mc-Si [1] random grain boundaries, although being recombination active, often enhance material quality by reducing dislocations. With this work, we take a step towards statistical large-scale investigations of crystal defects via a combined analysis of different inline-measurements on as-cut wafers: photoluminescence images for the extraction of recombination-active structures and reflection and infrared transmission images for the extraction of the grain structure. The combined extraction of recombination-active structures and grain structures allows isolating dislocations from grain boundaries for all material types. To discern dislocations from other recombination-active defect structures, an image-processing-based analysis technique has been developed. By applying this separation on wafers from various bricks of our material set, typical developments of grain structure and dislocations can be identified. As a particular application, we investigate the correlation between the development of dislocations in higher parts of the brick and grain size in the lower parts. The results support theory quantitatively: Dislocation ratio in the upper brick part shows a correlation with the square root of the weighted median of the grain size in the lower brick part (R≈0.85). However, the results also show that grain size distribution, in particular grain size homogeneity, has to be considered to account for a stronger distinction between materials.