中国物理B ›› 2022, Vol. 31 ›› Issue (12): 128105-128105.doi: 10.1088/1674-1056/ac9823

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Degradation mechanisms for polycrystalline silicon thin-film transistors with a grain boundary in the channel under negative gate bias stress

Dongli Zhang(张冬利)†, Mingxiang Wang(王明湘), and Huaisheng Wang(王槐生)   

  1. School of Electronic and Information Engineering, Soochow University, Suzhou 215006, China
  • 收稿日期:2022-08-05 修回日期:2022-09-29 接受日期:2022-10-07 出版日期:2022-11-11 发布日期:2022-11-11
  • 通讯作者: Dongli Zhang E-mail:dongli_zhang@suda.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 61971299 and 61974101), the Natural Science Foundation of Jiangsu Province of China (Grant No. BK20201201), the Fund from Suzhou Science and Technology Bureau (Grant No. SYG201933), and the Fund from the State Key Laboratory of ASIC and System, Fudan University (Grant No. 2021KF005).

Degradation mechanisms for polycrystalline silicon thin-film transistors with a grain boundary in the channel under negative gate bias stress

Dongli Zhang(张冬利)†, Mingxiang Wang(王明湘), and Huaisheng Wang(王槐生)   

  1. School of Electronic and Information Engineering, Soochow University, Suzhou 215006, China
  • Received:2022-08-05 Revised:2022-09-29 Accepted:2022-10-07 Online:2022-11-11 Published:2022-11-11
  • Contact: Dongli Zhang E-mail:dongli_zhang@suda.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 61971299 and 61974101), the Natural Science Foundation of Jiangsu Province of China (Grant No. BK20201201), the Fund from Suzhou Science and Technology Bureau (Grant No. SYG201933), and the Fund from the State Key Laboratory of ASIC and System, Fudan University (Grant No. 2021KF005).

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摘要： The negative gate bias stress (NBS) reliability of n-type polycrystalline silicon (poly-Si) thin-film transistors (TFTs) with a distinct defective grain boundary (GB) in the channel is investigated. Results show that conventional NBS degradation with negative shift of the transfer curves is absent. The on-state current is decreased, but the subthreshold characteristics are not affected. The gate bias dependence of the drain leakage current at Vds of 5.0 V is suppressed, whereas the drain leakage current at Vds of 0.1 V exhibits obvious gate bias dependence. As confirmed via TCAD simulation, the corresponding mechanisms are proposed to be trap state generation in the GB region, positive-charge local formation in the gate oxide near the source and drain, and trap state introduction in the gate oxide.

关键词: negative bias stress, poly-Si, thin-film transistor, grain boundary

Abstract: The negative gate bias stress (NBS) reliability of n-type polycrystalline silicon (poly-Si) thin-film transistors (TFTs) with a distinct defective grain boundary (GB) in the channel is investigated. Results show that conventional NBS degradation with negative shift of the transfer curves is absent. The on-state current is decreased, but the subthreshold characteristics are not affected. The gate bias dependence of the drain leakage current at Vds of 5.0 V is suppressed, whereas the drain leakage current at Vds of 0.1 V exhibits obvious gate bias dependence. As confirmed via TCAD simulation, the corresponding mechanisms are proposed to be trap state generation in the GB region, positive-charge local formation in the gate oxide near the source and drain, and trap state introduction in the gate oxide.

Key words: negative bias stress, poly-Si, thin-film transistor, grain boundary

中图分类号:  (Amorphous semiconductors)

  • 81.05.Gc
81.05.Ea (III-V semiconductors) 85.30.Tv (Field effect devices)