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Effects of Oxygen and Forming Gas Annealing on ZnO TFTs

Published online by Cambridge University Press:  15 July 2011

Jiaye Huang
Affiliation:
Fraunhofer Institute for Integrated Systems and Device Technology (IISB), Schottkystrasse 10, 91058 Erlangen, Germany
Ujwal Radhakrishna*
Affiliation:
Fraunhofer Institute for Integrated Systems and Device Technology (IISB), Schottkystrasse 10, 91058 Erlangen, Germany
Martin Lemberger
Affiliation:
Fraunhofer Institute for Integrated Systems and Device Technology (IISB), Schottkystrasse 10, 91058 Erlangen, Germany
Michael P.M. Jank
Affiliation:
Fraunhofer Institute for Integrated Systems and Device Technology (IISB), Schottkystrasse 10, 91058 Erlangen, Germany
Sebastian Polster
Affiliation:
Chair of Electron Devices, University of Erlangen-Nuremberg, Cauerstrasse 6, 91058 Erlangen, Germany
Heiner Ryssel
Affiliation:
Fraunhofer Institute for Integrated Systems and Device Technology (IISB), Schottkystrasse 10, 91058 Erlangen, Germany Chair of Electron Devices, University of Erlangen-Nuremberg, Cauerstrasse 6, 91058 Erlangen, Germany
Lothar Frey
Affiliation:
Fraunhofer Institute for Integrated Systems and Device Technology (IISB), Schottkystrasse 10, 91058 Erlangen, Germany Chair of Electron Devices, University of Erlangen-Nuremberg, Cauerstrasse 6, 91058 Erlangen, Germany
*
*Correspondence to: E-mail: [email protected].
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Abstract

ZnO TFTs with bottom gate top S/D contact architecture were fabricated by sputtering of ZnO with layer thicknesses from 30 nm to 100 nm. The effect of post deposition annealing in oxygen and forming gas atmospheres at 400°C to 500°C on the devices was investigated. The tendencies of a lower threshold voltage Vth and a higher saturation mobility μsat for higher annealing temperature can be observed for both oxygen and forming gas annealing. Reduction of trap density in oxygen annealing and additional hydrogen incorporation in forming gas annealing play an important role for these electrical parameters. Morphological changes of increased grain size and fewer grain boundaries in the channel also contribute to tendencies in electrical characteristics of ZnO TFTs.

Type
Research Article
Copyright
Copyright © Materials Research Society 2011

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References

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