a-IGZO TFT Based Pixel Circuits for AM-OLED Displays

In this paper, we analyze application of amorphous Indium– Gallium–Zinc–Oxide thin film transistors (a-InGaZnO TFTs) to voltage-driven pixel electrode circuit that could be used for 4.3in. wide video graphics array (WVGA) full color active-matrix organic light-emitting displays (AM-OLEDs). Simulation results, based on a-InGaZnO TFT and OLED experimental data, show that both device sizes and operational voltages can be reduced when compared to the same circuit using hydrogenated amorphous silicon (a-Si:H) TFTs. Moreover, the a-InGaZnO TFT pixel circuit can compensate for the threshold voltage variation (ΔVTH) of driving TFT within acceptable operating error range. *Corresponding author: [email protected] 2. a-InGaZnO TFT Model Extraction a-InGaZnO TFT SPICE model was developed based on the Rensselaer Polytechnic Institute (RPI) a-Si:H TFT model. Needed a-InGaZnO TFT SPICE parameters were extracted from Figure 1 Measured and simulated (a) transfer and (b) output characteristics of a-InGaZnO TFT. Simulation is performed by HSPICE. P-14 / H. Jung SID 2012 DIGEST • 1097 ISSN 0097-966X/12/4303-1097-$1.00 © 2012 SID