Premium
Passivation of aluminium–n + silicon contacts for solar cells by ultrathin Al 2 O 3 and SiO 2 dielectric layers
Author(s) -
Bullock James,
Yan Di,
Cuevas Andrés
Publication year - 2013
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201308115
Subject(s) - passivation , materials science , atomic layer deposition , dielectric , silicon , open circuit voltage , aluminium , thermal stability , analytical chemistry (journal) , annealing (glass) , optoelectronics , insulator (electricity) , thin film , layer (electronics) , voltage , electrical engineering , nanotechnology , composite material , chemistry , organic chemistry , chromatography , engineering
Ultra‐thin thermally grown SiO 2 and atomic‐layer‐deposited (ALD) Al 2 O 3 films are trialled as passivating dielectrics for metal–insulator–semiconductor (MIS) type contacts on top of phosphorus diffused regions applicable to high efficiency silicon solar cells. An investigation of the optimum insulator thickness in terms of contact recombination factor J 0_cont and contact resistivity ρ c is undertaken on 85 Ω/□ and 103 Ω/□ diffusions. An optimum ALD Al 2 O 3 thickness of ∼22 Å produces a J 0_cont of ∼300 fAcm –2 whilst maintaining a ρ c lower than 1 mΩ cm 2 for the 103 Ω/□ diffusion. This has the potential to improve the open‐circuit voltage by a maximum 15 mV. The thermally grown SiO 2 fails to achieve equivalently low J 0_cont values but exhibits greater thermal stability, resulting in slight improvements in ρ c when annealed for 10 minutes at 300 °C without significant changes in J 0_cont . The after‐anneal J 0_cont reaches ∼600 fAcm –2 with a ρ c of ∼2.5 mΩ cm 2 for the 85 Ω/□ diffusion amounting to a maximum gain in open‐circuit voltage of 6 mV. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)