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High‐quality amorphous silicon thin films for tunnel oxide passivating contacts deposited at over 150 nm/min
Author(s) -
Li Shenghao,
Pomaska Manuel,
Hoß Jan,
Lossen Jan,
Qiu Kaifu,
Hong Ruijiang,
Finger Friedhelm,
Rau Uwe,
Ding Kaining
Publication year - 2021
Publication title -
progress in photovoltaics: research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.286
H-Index - 131
eISSN - 1099-159X
pISSN - 1062-7995
DOI - 10.1002/pip.3333
Subject(s) - passivation , materials science , amorphous silicon , silicon , amorphous solid , microstructure , doping , deposition (geology) , chemical vapor deposition , oxide , crystallization , chemical engineering , thin film , nanotechnology , layer (electronics) , optoelectronics , crystalline silicon , composite material , metallurgy , chemistry , paleontology , organic chemistry , sediment , engineering , biology
Hot‐wire chemical vapor deposition was utilized to develop rapidly grown and high‐quality phosphorus‐doped amorphous silicon (a‐Si:H) thin films for poly‐crystalline silicon on tunnel oxide carrier‐selective passivating contacts. Deposition rates higher than 150 nm/min were obtained for the in situ phosphorus‐doped a‐Si:H layers. To optimize the passivating contact performance, material properties such as microstructures as well as hydrogen content were characterized and analyzed for these phosphorus‐doped a‐Si:H films. The results show that a certain microstructure of the films is crucial for the passivation quality and the conductance of passivating contacts. Porous silicon layers were severely oxidized during high‐temperature crystallization, giving rise to very low conductance. The insufficient effective doping concentration in these layers also yields inferior passivation quality due to lack of field‐effect passivation. On the other hand, dense silicon layers are insensitive to oxidation but very sensitive to blistering of the films during the subsequent high‐temperature process steps. By optimizing the deposition parameters, a firing‐stable‐implied open‐circuit voltage of 737 mV and a contact resistivity of 10 mΩ·cm 2 were achieved at a high deposition rate of 100 nm/min while 733 mV and 90 mΩ·cm 2 were achieved at an even higher deposition rate of 150 nm/min.