Reduction of Negative Bias and Light Instability of a-IGZO TFTs by Dual-Gate Driving

Author

Sejin Hong ; Suhui Lee ; Mativenga, Mallory ; Jin Jang

Author_Institution

Dept. of Inf. Display, Kyung Hee Univ., Seoul, South Korea

Volume

35

Issue

1

fYear

2014

fDate

Jan. 2014

Firstpage

93

Lastpage

95

Abstract

Stability under negative-bias-illumination-stress (NBIS) of dual-gate (top- and bottom-gate) amorphous-indium-gallium-zinc-oxide (a-IGZO) thin-film transistors is investigated. It is found that the negative threshold-voltage shift (ΔV_TH) induced by NBIS is much smaller under dual-gate driving (when the two gates are electrically tied together) compared with single-gate driving. For a 20 nm-thick a-IGZO active layer, this is attributed to bulk accumulation, where electrons are accumulated across the entire depth of the active layer, which is responsible for the small negative ΔV_TH after NBIS. Due to bulk accumulation, the Fermi level can be easily shifted by dual-gate driving as compared with the conventional single-gate driving, even after NBIS.

Keywords

II-VI semiconductors; amorphous semiconductors; gallium compounds; indium compounds; thin film transistors; wide band gap semiconductors; zinc compounds; In-Ga-Zn-O; NBIS; a-IGZO TFTs; bulk accumulation; dual gate amorphous-indium-gallium-zinc-oxide thin-film transistors; dual-gate driving; negative bias reduction; negative threshold-voltage shift; negative-bias-illumination-stress; single-gate driving; size 20 nm; Logic gates; Semiconductor device measurement; Sputtering; Stress; Thin film transistors; Time measurement; TFT; a-IGZO; bulk accumulation; dual gate; negative bias illumination stress (NBIS);

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/LED.2013.2290740

Filename

6677564