Dynamic Response of a-InGaZnO and Amorphous Silicon Thin-Film Transistors for Ultra-High Definition Active-Matrix Liquid Crystal Displays

Author

Yu, Eric Kai-Hsiang ; Rui Zhang ; Linsen Bie ; Kuo, Alex ; Kanicki, Jerzy

Author_Institution

Dept. of Electr. Eng. & Comput. Sci., Univ. of Michigan, Ann Arbor, MI, USA

Volume

11

Issue

5

fYear

2015

fDate

May-15

Firstpage

471

Lastpage

479

Abstract

The dynamic response of hydrogenated amorphous silicon (a-Si:H) thin-film transistor (TFT) and amorphous In-Ga-Zn-O (a-IGZO) T_FT are compared. We study the storage capacitor (Cst) charging characteristics by applying gate and data voltage waveforms corresponding to ultra-high definition (UHD) active-matrix liquid crystal displays (AM-LCDs). We show that the charging behavior of the a-Si:H T_FT is insufficient for UHD AM-LCDs and that the a-IGZO T_FT is capable of supporting at least 8 K ×4 K display resolution at 480 Hz. The impact of C_st and gate voltage falling edge (t_FE) on feedthrough voltage (ΔV_P) is investigated. Because of higher mobility of the a-IGZO T_FT, it is possible to reduce ΔV_P by mitigating channel charge redistribution with non-abrupt tFE. The a-IGZO TFT shows no drawbacks in terms of ΔV_P when compared to the a-Si:H T_FT. In addition, a larger C_st can be used in combination with the a-IGZO T_FT to reduce ΔV_P with minimal impact on its charging behavior. Gate overdrive operation is also evaluated for the a-IGZO T_FT, which may improve charging characteristics with no adverse effects on ΔV_P. Our results show that the a-IGZO T_FT is a suitable technology for UHD high-frame rate AM-LCDs.

Keywords

capacitor storage; elemental semiconductors; gallium compounds; indium compounds; liquid crystal displays; silicon; thin film transistors; IGZO; InGaZnO; Si; TFT; UHD AM-LCD; channel charge mitigation; data voltage waveform; dynamic response; frequency 480 Hz; gate overdrive operation; gate voltage falling edge; hydrogenated amorphous silicon thin-film transistor; storage capacitor charging characteristics; ultra-high definition active-matrix liquid crystal display; Amorphous silicon; Capacitance; Capacitors; Electrodes; Logic gates; Thin film transistors; AM-LCD; Active-matrix; a-IGZO; amorphous silicon; dynamic response; falling edge; feedthrough voltage; flat-panel displays; overdrive; thin-film transistors (TFTs); ultra-high definition;

fLanguage

English

Journal_Title

Display Technology, Journal of

Publisher

ieee

ISSN

1551-319X

Type

jour

DOI

10.1109/JDT.2015.2416209

Filename

7066937