Robust Gate Driver on Array Based on Amorphous IGZO Thin-Film Transistor for Large Size High-Resolution Liquid Crystal Displays

Abstract

Amorphous IGZO thin-film transistors (TFTs) in an etch stop layer (ESL) structure was processed on 2500 mm × 2200 mm size substrate. The fabricated devices exhibit enhancement mode characteristics, and excellent uniformity over large area. The presented good operational stabilities under both positive gate bias temperature stress (PBTS) and negative gate bias temperature stress (NBTS) tests can well meet the requirements for pixel switching. However, considering even threshold voltage shift under long term positive bias stress might affect proper operation of the gate driver on array (GOA), a design with a pulse gating scheme is proposed, consisting of 13 TFTs and 1 capacitor, to avoid long term continuous bias stressing of the TFT. With the proposed GOA design, a 32-inch QUHD (7680×4320) highresolution liquid crystal display (LCD) panel with a 7 mm wide bezel is achieved. The reliability of the GOA circuit is well proved through standard aging tests.

Keywords

• Thin-film transistor
• IGZO
• gate driver
• stability