Reduction of charge trapping in HfO2 film on a Ge substrate by trimethylaluminum pretreatment

Trimethylaluminum pretreatment prior to HfO2 deposition is introduced for native oxide reduction. It is identified that the trimethylaluminum pretreatment could effectively reduce native oxide, which is transformed to an aluminum oxide interfacial layer. Formation of the thin aluminum oxide layer su...

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Bibliographic Details
Published in:Physica status solidi. PSS-RRL. Rapid research letters 2012-11, Vol.6 (11), p.439-441
Main Authors: Lee, Jae Jin, Shin, Yunsang, Choi, Juyun, Kim, Hyoungsub, Hyun, Sangjin, Choi, Siyoung, Cho, Byung Jin, Lee, Seok-Hee
Format: Article
Language:English
Subjects:
Aluminum
charge trapping
germanium
HfO2
native oxide
Oxidation
Thin films
trimethylaluminum
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Summary:Trimethylaluminum pretreatment prior to HfO2 deposition is introduced for native oxide reduction. It is identified that the trimethylaluminum pretreatment could effectively reduce native oxide, which is transformed to an aluminum oxide interfacial layer. Formation of the thin aluminum oxide layer suppresses Ge diffusion into HfO2, reducing hysteresis in the ca‐ pacitance–voltage curve. Moreover, the device reliability of the trimethylaluminum pretreated sample is improved in a constant current stress test. This work indicates that trimethylaluminum pretreatment is an effective in‐situ method for the gate dielectric stack formation to reduce charge trapping in the HfO2 film on a Ge substrate. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) Trimethylaluminum (TMA) pretreatment prior to atomic layer deposition of HfO2 on a Ge substrate is introduced. Secondary ion mass spectroscopy reveals less Ge diffusion into the HfO2 film after TMA pretreatment because the germanium native oxide is converted to aluminum oxide, resulting in a capacitance–voltage hysteresis reduction and improved device reliability.
ISSN:1862-6254
1862-6270
DOI:10.1002/pssr.201206315