An a-IGZO TFT Based AMOLED Pixel Circuit Employing Stable Mobility Compensation Suppressing Degradation of Detected VTH

• Published in: IEEE journal of the Electron Devices Society Vol. 12; p. 1
• Main Authors: Kang, Kyeong-Soo, Park, Ji-Hwan, Park, ChanJin, Lee, Ji-Ho, Lee, Soo-Yeon
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-01-2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: a-IGZO; Active matrix displays; Capacitors; Circuits; Compensation; Gallium; high-PPI; Indium gallium zinc oxide; mobility; Organic light emitting diodes; pixel circuit; Pixels; Semiconductor devices; Switches; TFT; Thin film transistors; Threshold voltage; Timing; Voltage measurement; VTH; Zinc oxide
• ISSN: 2168-6734
• DOI: 10.1109/JEDS.2023.3331702

In this paper, we propose a new active-matrix organic light-emitting diode (AMOLED) pixel circuit using amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors (TFTs). The proposed pixel circuit consists of seven TFTs and two capacitors, compensating for both threshold voltage (VTH) and mobility variations. The simulation results show that the proposed pixel circuit can successfully compensate for mobility variation. Also, the mobility compensation stage positively affects a significant VTH fluctuation. The proposed circuit is fabricated within an area of 19.95 μm × 39.9 μm that can achieve 635 pixels per inch (PPI), and the experimental results show relatively consistent current levels even under severe TFT variations.