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Fracture Strength of Photovoltaic Silicon Wafers Evaluated Using a Controlled Flaw Method
Author(s) -
Shi Meirong,
Youssef Khaled,
Rozgonyi George A.
Publication year - 2013
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201200312
Subject(s) - wafer , materials science , silicon , composite material , fracture (geology) , cracking , breakage , photovoltaic system , residual stress , fracture mechanics , metallurgy , optoelectronics , electrical engineering , engineering
Propagation of pre‐existing micro cracks and their associated residual contact stresses, generated from the wafer sawing process, is the leading cause for photovoltaic (PV) silicon wafer/cell breakage during handling and processing. In the current work, the impact of a single micro crack on the fracture strength of PV silicon wafer is investigated based on a controlled flaw method. Radial/median cracks with controllable scales are introduced through microindentation at the center of a PV silicon sample to simulate micro cracks resulting from wafer sawing, handling, or thermal processing. Results indicate that the fracture strength of PV silicon wafer decreases linearly with the increasing of the microindentation load (radial crack scale). In addition, it is found that the impurity carbon plays an important role in the contact cracking‐fracture process. The fracture strength increased ≈21% when the substitutional carbon concentration is increased from 1.2 × 10 18 to 6.4 × 10 18 cm −3 .