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Title:
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Mechanical strength of silicon wafers and its modelling
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Author(s):
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Published by:
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Publication date:
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ECN
Solar Energy
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1-8-2005
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ECN report number:
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Document type:
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ECN-RX--05-133
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Conference Paper
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Number of pages:
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Full text:
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4
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Download PDF
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Presented at: 15th Workshop on Crystalline Silicon Solar Cells & Modules: Materials and Processes, Vail CO, USA, 7-10 augustus 2005.
Abstract:
Mechanical strength measurements of multicrystalline Si wafers are carriedout with a ring-on-ring test geometry. This geometry is very sensitive
to the surface of the wafers rather than the edge. The measurements
reveal the great importance of the saw damage on the mechanical stability
of as-cut as well as textured wafers. The initial surface defects make
a big and unexpected difference in the strength after a standard industrial
acid etch. The strength analysis of wafers from different manufacturers
shows no influence of bulk defects on strength. This geometry therefore
permits to focus on the modification of mechanical stability by adaptations
of, e.g., wafering or chemical treatment. The stress at breakage is
translated into an apparent critical crack length, which can be used
as an intuitive parameter to quantify the surface damage. The relationship
between breakage force and wafer thickness from linear plate theory
is analysed and verified.
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