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Iron‐related carrier traps near the n + p‐junctions of crystalline silicon solar cells: impacts of feedstock and of the fabrication processes
Author(s) -
Mchedlidze Teimuraz,
Weber Jörg
Publication year - 2014
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201451021
Subject(s) - fabrication , wafer , materials science , solar cell , silicon , crystalline silicon , carrier lifetime , diffusion , optoelectronics , medicine , alternative medicine , physics , pathology , thermodynamics
An influence of the iron content in the crystal on the formation of carrier traps in the silicon solar cells was studied. Mesa‐structured n + p‐junctions were formed on the surface of Cz‐Si wafers after various stages of a standard solar cell fabrication process. Majority carrier traps in/near the junction volume were investigated by deep level transient spectroscopy (DLTS). The trap density correlated with the total iron content in the wafers and dropped strongly with the distance from the junctions. Our results suggest that the traps were formed during the phosphorus diffusion process and/or during the subsequent cooling. The initial iron content in the wafers influenced changes in the trap concentrations at further fabrication steps. The present study could help in increasing solar cell efficiencies by tailoring the fabrication processes according to the contamination in the feedstock.