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Improvement of Surface Passivation of Tunnel Oxide Passivated Contact Structure by Thermal Annealing in Mixture of Water Vapor and Nitrogen Environment
Author(s) -
Zhang Zhi,
Liao Mingdun,
Huang Yuqing,
Guo Xueqi,
Yang Qing,
Wang Zhixue,
Gao Tian,
Shou Chunhui,
Zeng Yuheng,
Yan Baojie,
Ye Jichun
Publication year - 2019
Publication title -
solar rrl
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.544
H-Index - 37
ISSN - 2367-198X
DOI - 10.1002/solr.201900105
Subject(s) - passivation , forming gas , annealing (glass) , materials science , crystallization , oxide , water vapor , nitrogen , carrier lifetime , solar cell , silicon , secondary ion mass spectrometry , crystalline silicon , analytical chemistry (journal) , chemical engineering , optoelectronics , composite material , ion , metallurgy , chemistry , environmental chemistry , layer (electronics) , organic chemistry , engineering
The effects of post‐crystallization annealing within various atmospheres on the surface passivation quality of tunnel oxide passivated contact (TOPCon) for crystalline silicon (c‐Si) solar cells are studied. The results provide an innovative method for improving the surface passivation of the as‐crystallized TOPCon structure by annealing at moderate temperatures ranging from 300 to 700 °C within a mixture of water vapor and nitrogen atmosphere. The wet nitrogen improves the implied open‐circuit voltages ( iV oc ) from 700–710 to ≈730 mV on average and reduces the single‐side reverse saturated recombination current density ( J 0 ) to 3.8 fA cm −2 , which is much more effective than the so‐called forming‐gas annealing. In addition, the contact resistivity remains in low values of ≈5 mΩ cm 2 , ensuring its application in the high‐efficiency c‐Si solar cell. Secondary ion mass spectroscopy provides the evidence that the enhanced surface passivation by the water vapor annealing results from the hydrogen incorporation, which is logically believed to passivate the defects in the oxide and c‐Si interface region. This study proposes a simple and cost‐effective technique to improve the surface passivation of TOPCon structure, which is suitable for the high‐efficiency c‐Si solar‐cell manufacture.