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Effects of Pre‐annealing on Firing Stability of Atomic Layer‐Deposited Al 2 O 3
Author(s) -
Bae Soohyun,
Kim Soo Min,
Lee Kyung Dong,
Kim Young Do,
Park Sungeun,
Kang Yoonmook,
Lee HaeSeok,
Kim Donghwan
Publication year - 2015
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.201400192
Subject(s) - passivation , annealing (glass) , wafer , chemistry , atomic layer deposition , analytical chemistry (journal) , thermal stability , metal , capacitance , silicon , electrode , optoelectronics , layer (electronics) , metallurgy , materials science , organic chemistry , chromatography
Al 2 O 3 layers fabricated with atomic layer deposition (ALD) show high levels of surface passivation on p‐ and n‐type silicon wafers. In order to form front and rear electrodes, Al 2 O 3 layers should undergo a firing process at a high peak temperature. Therefore, the Al 2 O 3 layer must be stable under these conditions to maintain a high level of surface passivation during the firing process. In this study, Al 2 O 3 layers fabricated with ALD were pre‐annealed to enhance their thermal stability during the firing process. From quasi‐steady state photoconductance (QSSPC) measurements, the difference between the implied V oc values of the pre‐annealed and fired samples was found to be smallest (3 mV) when the sample was pre‐annealed at 620 °C. The surface recombination rate calculated from capacitance‐voltage ( C ‐ V ) measurements of metal‐Al 2 O 3 ‐Si (metal‐insulator‐semiconductor) structures was shown to be low when the sample was pre‐annealed at 600–650 °C. Thus, firing stability was achieved with pre‐annealing at 620 °C by reducing the surface recombination rate. We conclude that it is necessary to pre‐anneal the Al 2 O 3 passivation layer at this specific temperature to reduce the degradation of the passivation quality of Al 2 O 3 after the firing process.