Effect of surface treatments on interfacial characteristics and band alignments of atomic‐layer‐deposited Al 2 O 3  films on GaAs substrates | Zendy

Gong YouPin | Zendy; Li AiDong | Zendy; Liu XiaoJie | Zendy; Zhang WenQi | Zendy; Li Hui | Zendy; Wu Di | Zendy

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Effect of surface treatments on interfacial characteristics and band alignments of atomic‐layer‐deposited Al 2 O 3 films on GaAs substrates

Author(s) -

Gong YouPin,

Li AiDong,

Liu XiaoJie,

Zhang WenQi,

Li Hui,

Wu Di

Publication year - 2011

Publication title -

surface and interface analysis

Language(s) - English

Resource type - Journals

SCImago Journal Rank - 0.52

H-Index - 90

eISSN - 1096-9918

pISSN - 0142-2421

DOI - 10.1002/sia.3591

Subject(s) - passivation , annealing (glass) , atomic layer deposition , suboxide , materials science , conduction band , band gap , layer (electronics) , dielectric , band offset , analytical chemistry (journal) , chemistry , optoelectronics , valence band , nanotechnology , silicon , metallurgy , electron , physics , quantum mechanics , chromatography

The GaAs surfaces were passivated by two kinds of chemical pretreatments (using NH 4 OH and (NH 4 ) 2 S as passivation agents) for atomic layer deposited (ALD) Al 2 O 3 dielectric film growth. The chemical information at Al 2 O 3 /GaAs interfaces was carefully characterized. The impact of surface treatments on the band alignments of ALD Al 2 O 3 films on nGaAs (100) substrates was also investigated. After postdeposition annealing, the NH 4 OH passivated samples not only have a slight increase of the AsAs peaks with an appearance of As suboxide (AsO x ) feature at Al 2 O 3 /GaAs interfaces but also exhibit a serious interfacial interdiffusion between Al 2 O 3 and GaAs. However, the (NH 4 ) 2 S passivated samples produce the GaS and AsS overlayers on GaAs, effectively preventing from the intermixed diffusion between Al 2 O 3 films and GaAs substrates with a sharper interface. Both NH 4 OH and (NH 4 ) 2 S passivated Al 2 O 3 samples show the same band gap of 6.67 eV. The conduction band offset at Al 2 O 3 /GaAs interface for the (NH 4 ) 2 S passivated samples have a slight enhancement of 0.14 eV in comparison to NH 4 OH passivated ones. Copyright © 2010 John Wiley & Sons, Ltd.

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