56.4: Dual‐Gate IGZO TFT for Threshold‐ Voltage Compensation in AMOLED Pixel Circuit

Abstract

In addition to the gate electrode at the bottom, a dual-gate InGaZnO 4 (a-IGZO) thin film transistor (TFT) has a secondary gate electrode on the top. The threshold voltage of the TFT using the bottom-gate in its normal operation can be controlled by the top-gate. Based on this phenomenon, a new concept of using the top-gate to compensate threshold voltage variation is proposed. This new technique is demonstrated in two pixel circuits of active-matrix organic light-emitting diode and verified by the measurement results.

Transparent AMOLED display driven by split oxide TFT backplane

“…After this, a 150‐nm Mo was deposited and patterned as the source/drain electrodes, followed by the deposition of PECVD SiO 2 layer as the passivation layer. An IZO layer is deposited and patterned to form the pixel electrode, anode for OLED . Then, to form the transparent OLED stack, 1,4,5,8,9,11‐hexaazatriphenylene‐hexacarbonitrile (HAT‐CN) (20 nm) as a hole injection layer, N , N ′‐di(naphthalene‐1‐yl)‐ N , N ′‐diphenylbenzidine (NPB) (50 nm) as a hole transport layer, 4,4′,4′‐tris(carbazol‐9‐yl)‐triphenylamine (TCTA) (5 nm) as an exciton blocking layer, TCTA:2,2′,2′‐(1,3,5‐benzenetriyl)‐tris‐[1‐phenyl‐1‐H‐benzimidazole] (TPBi):12% tris(2‐phenylpyridinato‐C2, N )iridium(III) (Ir(ppy) 3 ) (15 nm) as an emission layer, TPBi (45 nm) as an electron transport layer, and LiF (0.5 nm)/Al (1 nm)/Ag (22 nm) as a transparent cathode.…”

19‐2: Distinquished Student Paper: Transparent AMOLED Display Driven by Split Oxide TFT Backplane

“…The additional output node is necessary to separate the output to the next stage from the panel to improve yield by reducing the influence of particles during the fabrication process, which may result in short or open in the gate/data lines and gate insulator/interlayer. The operational principle is similar to the one presented elsewhere [8] . The performance of 124-stages shift resistor with split structures, which functions well up to the last stage as shown in Fig.4(d) indicating Input signal and last stage (124 th ) output.…”

Highly robust oxide TFT with bulk accumulation and source/drain/active layer splitting

“…Recently, amorphous indium‐gallium‐zinc oxide (a‐IGZO) TFT is being used for AMOLED TV, but the mobility should be further improved for its wide application. Therefore, high‐mobility a‐IGZO TFT is getting more attention recently . Furthermore, to realize a flexible AMOLED display, the electrical and mechanical stabilities of AOS‐based devices are being studied.…”

“…Therefore, high-mobility a-IGZO TFT is getting more attention recently. 7,8 Furthermore, to realize a flexible AMOLED display, the electrical and mechanical stabilities of AOS-based devices are being studied.…”