JSTS:Journal of Semiconductor Technology and Science

The Institute of Electronics and Information Engineers (대한전자공학회)
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Analysis of Instability Mechanism under Simultaneous Positive Gate and Drain Bias Stress in Self-Aligned Top-Gate Amorphous Indium-Zinc-Oxide Thin-Film Transistors

  • Kim, Jonghwa (School of Electrical Engineering, Kookmin University) ;
  • Choi, Sungju (School of Electrical Engineering, Kookmin University) ;
  • Jang, Jaeman (School of Electrical Engineering, Kookmin University) ;
  • Jang, Jun Tae (School of Electrical Engineering, Kookmin University) ;
  • Kim, Jungmok (School of Electrical Engineering, Kookmin University) ;
  • Choi, Sung-Jin (School of Electrical Engineering, Kookmin University) ;
  • Kim, Dong Myong (School of Electrical Engineering, Kookmin University) ;
  • Kim, Dae Hwan (School of Electrical Engineering, Kookmin University)
  • Received : 2015.04.20
  • Accepted : 2015.09.15
  • Published : 2015.10.30
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Abstract

We quantitatively investigated instability mechanisms under simultaneous positive gate and drain bias stress (SPGDBS) in self-aligned top-gate amorphous indium-zinc-oxide thin-film transistors. After SPGDBS ($V_{GS}=13V$and $V_{DS}=13V$), the parallel shift of the transfer curve into a negative $V_{GS}$ direction and the increase of on current were observed. In order to quantitatively analyze mechanisms of the SPGDBS-induced negative shift of threshold voltage (${\Delta}V_T$), we experimentally extracted the density-of-state, and then analyzed by comparing and combining measurement data and TCAD simulation. As results, 19% and 81% of ${\Delta}V_T$ were taken to the donor-state creation and the hole trapping, respectively. This donor-state seems to be doubly ionized oxygen vacancy ($V{_O}^{2+}$). In addition, it was also confirmed that the wider channel width corresponds with more negative ${\Delta}V_T$. It means that both the donor-state creation and hole trapping can be enhanced due to the increase in self-heating as the width becomes wider. Lastly, all analyzed results were verified by reproducing transfer curves through TCAD simulation.

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References

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