CUED Publications database

Interpreting anomalies observed in oxide semiconductor TFTs under negative and positive bias stress

Jin, JW and Nathan, A and Barquinha, P and Pereira, L and Fortunato, E and Martins, R and Cobb, B (2016) Interpreting anomalies observed in oxide semiconductor TFTs under negative and positive bias stress. AIP Advances, 6.

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Abstract

© 2016 Author(s). Oxide semiconductor thin-film transistors can show anomalous behavior under bias stress. Two types of anomalies are discussed in this paper. The first is the shift in threshold voltage (V TH ) in a direction opposite to the applied bias stress, and highly dependent on gate dielectric material. We attribute this to charge trapping/detrapping and charge migration within the gate dielectric. We emphasize the fundamental difference between trapping/detrapping events occurring at the semiconductor/dielectric interface and those occurring at gate/dielectric interface, and show that charge migration is essential to explain the first anomaly. We model charge migration in terms of the non-instantaneous polarization density. The second type of anomaly is negative V TH shift under high positive bias stress, with logarithmic evolution in time. This can be argued as electron-donating reactions involving H 2 O molecules or derived species, with a reaction rate exponentially accelerated by positive gate bias and exponentially decreased by the number of reactions already occurred.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div B > Solid State Electronics and Nanoscale Science
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 18:57
Last Modified: 03 Aug 2017 03:04
DOI: