Instability mechanisms in amorphous oxide semiconductors leading to a threshold voltage shift in thin film transistors
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Publication Date
2017-05-01Journal Title
ECS Transactions
ISSN
1938-5862
Publisher
Electrochemical Society
Volume
79
Issue
1
Pages
49-56
Language
English
Type
Article
This Version
AM
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Flewitt, A., & Niang, K. (2017). Instability mechanisms in amorphous oxide semiconductors leading to a threshold voltage shift in thin film transistors. ECS Transactions, 79 (1), 49-56. https://doi.org/10.1149/07901.0049ecst
Abstract
Amorphous indium gallium zinc oxide (a-IGZO) has been successfully employed commercially as the channel layer in thin film transistors (TFTs) for active-matrix flat panel displays. However, these TFTs are known to suffer from a threshold voltage shift upon application of a gate bias. The threshold voltage shift is reversible through annealing. A similar phenomenon is observed in other TFTs with an amorphous oxide semiconductor channel. The migration of oxygen vacancies is proposed as being the microscopic mechanism causing this effect as it can lead to a change in the equilibrium distribution of defect states in the band gap of the semiconductor. This would manifest itself as a reversible threshold voltage shift in the TFT transfer characteristics, as observed experimentally.
Sponsorship
The support of this work by the Engineering and Physical Sciences Research Council (EPSRC) through project EP/M013650/1 is acknowledged.
Funder references
EPSRC (EP/M013650/1)
Identifiers
External DOI: https://doi.org/10.1149/07901.0049ecst
This record's URL: https://www.repository.cam.ac.uk/handle/1810/265681
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