Effect of Bulk-Accumulation on Switching Speed of Dual-Gate a-IGZO TFT-Based Circuits

Author

Xiuling Li ; Di Geng ; Mativenga, Mallory ; Yuanfeng Chen ; Jin Jang

Author_Institution

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

Volume

35

Issue

12

fYear

2014

fDate

Dec. 2014

Firstpage

1242

Lastpage

1244

Abstract

The effect of bulk accumulation on switching speed of dual-gate amorphous indium-gallium-zinc-oxide thin-film transistor (TFT)-based circuits is investigated. Given that bulk accumulation is achieved by synchronized driving of the top gate (TG) and bottom gate, it can be modulated by varying the length of the TG (L_TG) for fixed source-drain distance (L). It is confirmed from fabricated ring oscillators that switching speed increases with increasing L_TG for fixed L, verifying that bulk accumulation improves switching speed. However, switching speed drops dramatically when the TG overlaps the source/drain electrodes due to additional parasitic capacitance. TFT-circuits with the longest, but nonoverlapping TGs are demonstrated to exhibit the fastest switching speed; operation frequency exceeding 2.63 MHz for input voltage V_DD of 20 V, which is also the fastest among all inverted staggered amorphous-oxide-semiconductor TFT-based circuits.

Keywords

gallium compounds; indium compounds; oscillators; thin film transistors; zinc compounds; InGaZnO; TFT; amorphous-oxide-semiconductor; bulk accumulation effect; dual-gate amorphous thin-film transistor; fixed source-drain distance; frequency 2.63 MHz; ring oscillators; source/drain electrodes; voltage 20 V; Capacitance; Electrodes; Indium gallium zinc oxide; Ring oscillators; Switching circuits; Thin film transistors; a-IGZO TFTs; dual-gate; ring-oscillator; ring-oscillator.;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/LED.2014.2362992

Filename

6937158