1. Positive-Bias Temperature Instability Improvement of Poly-Si Thin-Film Transistor With HfO2 Gate Dielectric by Ammonia Plasma Treatment.
- Author
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Ma, William Cheng-Yu, Lin, Zheng-Yi, Huang, Yao-Sheng, Huang, Bo-Siang, and Wu, Zheng-Da
- Subjects
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PLASMA gases , *DIELECTRICS , *SURFACE preparation , *THIN film transistors , *HAFNIUM compounds - Abstract
In this paper, positive-bias temperature instability (PBTI) stress with different stress voltage at T = 125~^\circ \textC is executed on the high-performance polycrystalline silicon (poly-Si) thin-film transistors (TFTs) with HfO2 gate dielectric and ammonia (NH3) plasma surface treatment. The NH3 plasma surface treatment on the poly-Si TFT with HfO2 gate dielectric can significantly decrease the threshold voltage ( V\mathrm{ TH} ) approximately −1.86 V, reduce the subthreshold slope (S.S.) approximately −88 mV/decade, enhance the transconductance ( Gm ) approximately 2.4\times , and driving current ( I_{\mathrm{ drv}}) approximately 2.34. In addition, the device degradation after PBTI stress with stress voltage V_{G} - V_{\mathrm{ TH}} = 7 V for 1000 s at T = 125~^\circ \textC can also be improved after the NH3 plasma surface treatment, such as the suppressing of V\mathrm TH shift from 2.063 to 0.617 V, S.S. degradation quantity from 0.284 V/decade to 0.172 V/decade, and I\mathrm{ drv} reduction from −77% to −44%. The improvement of the PBTI of poly-Si TFTs with NH3 plasma surface treatment is attributed to the suppression of oxide charge trapping effect and the degradation of interface state density ( N\mathrm{ it} ) and grain boundary trap state density ( N\mathrm{ GB} ). [ABSTRACT FROM AUTHOR]
- Published
- 2016
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