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Journal of Display Technology

Journal of Display Technology


  • Vol. 9, Iss. 12 — Dec. 1, 2013
  • pp: 985–988

Channel Length Dependent Bias-Stability of Self-Aligned Coplanar a-IGZO TFTs

Su Hwa Ha, Dong Han Kang, In Kang, Ji Ung Han, Mallory Mativenga, and Jin Jang

Journal of Display Technology, Vol. 9, Issue 12, pp. 985-988 (2013)

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We report channel length $L$ ( $L$ ranging from 2 to 40 $ \mu{{m}}$ ) dependence of the electrical stability of amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs). The a-IGZO TFTs employ a coplanar structure with a ${{SiN}}_{x}$ interlayer used to dope the source/drain regions. After application of positive gate bias stress (PBS), short-channel devices ( $L = 2~ \mu {{m}}$ ) exhibit smaller threshold voltage shifts ( $\Delta {\rm V} _{\rm th}$ ) compared to longer-channel devices ( $L \ge {4}~ \mu{{m}}$ ). It is proposed that carrier diffusion takes place from the high carrier concentration regions under the ${{SiN}}_{x}$ interlayer to the intrinsic channel region, thereby shifting the Fermi level closer to the conduction band. Higher Fermi levels mean less defect states available for carrier trapping – hence the small $\Delta {\rm V} _{\rm th}$ in short devices under PBS.

© 2013 IEEE

Su Hwa Ha, Dong Han Kang, In Kang, Ji Ung Han, Mallory Mativenga, and Jin Jang, "Channel Length Dependent Bias-Stability of Self-Aligned Coplanar a-IGZO TFTs," J. Display Technol. 9, 985-988 (2013)

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