Effects of Ta incorporation in Y2O3 gate dielectric of InGaZnO thin-film transistor

The effects of Ta incorporation in Y2O3 gate dielectric on the electrical characteristics of InGaZnO thin-film transistor are investigated. With an appropriate Ta content in the Y2O3 gate dielectric, the saturation mobility of the thin-film transistor can be significantly increased, about three time...

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Bibliographic Details
Published in:Applied physics letters 2016-10, Vol.109 (16)
Main Authors: Song, J. Q., Qian, L. X., Lai, P. T.
Format: Article
Language:English
Subjects:
Applied physics
Atomic force microscopy
Dielectrics
Hygroscopicity
Incorporation
Interface roughness
Noise measurement
Saturation
Silicon
Thin films
Threshold voltage
Transistors
Yttrium oxide
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Summary:The effects of Ta incorporation in Y2O3 gate dielectric on the electrical characteristics of InGaZnO thin-film transistor are investigated. With an appropriate Ta content in the Y2O3 gate dielectric, the saturation mobility of the thin-film transistor can be significantly increased, about three times that of the control sample with Y2O3 gate dielectric. Accordingly, the sample with a Ta/Ta+Y ratio of 68.6% presents a high saturation mobility of 33.5 cm2 V−1 s−1, low threshold voltage of 2.0 V, large on/off current ratio of 2.8 × 107, and suppressed hysteresis. This can be attributed to the fact that the Ta incorporation can suppress the hygroscopicity of Y2O3 and thus reduces the Y2O3/InGaZnO interface roughness and also the traps at/near the interface, as supported by atomic force microscopy and low-frequency noise measurement, respectively. However, excessive Ta incorporation in the Y2O3 gate dielectric leads to degradation in device performance because Ta-related defects are generated.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4965849