Recently, oxide semiconductors have assumed a pivotal role in electronic displays and transparent electronic devices such as amorphous indium gallium zinc oxide (a-IGZO), characterized by high electron mobility and excellent stability. a- IGZO is very suitable for next-generation applications such as flexible displays because it is possible to manufacture highperformance transistors even at low temperatures. However, since the electrical properties tend to deteriorate in hightemperature environments, research aimed at improving thermal stability is needed. In this study, a low-temperature plasma annealing process was introduced to improve the high-temperature stability of the a-IGZO thin film. This process enhances electron mobility by reducing defects in the a-IGZO film and provides stable device performance even under high-temperature conditions. As a result of the experiments of 5 min, 10 min, 15 min, and 20 min, the a-IGZO TFT, which was subjected to plasma annealing at 160℃ for 5 min, showed the best electrical performance, especially in charge mobility and current-voltage characteristics. The technical potential for improving the performance of a-IGZO-based display device was emphasized, and the foundation for applying this power generation to flexible displays and next-generation electronic devices was laid. Future research will focus on determining the optimal annealing conditions by exploring various temperature ranges and plasma parameters to integrate these results into the actual device manufacturing process. These efforts are expected advance significantly to advancing next-generation high-performance display technology.

The display industry has recently been at the forefront of innovative advancements in modern electronic devices. Technological progress such as flexible display holds significant potential across various application fields, particularly in wearable devices and rollable displays. A low-temperature process is essential for fabricating such displays. One of the key technologies in displays is the thin film transistor (TFT), with amorphous indium gallium zinc oxide (a-IGZO) receiving particular attention. a-IGZO is widely applied in high-performance displays due to its high charge mobility and stability. While a thermal treatment above 350℃ is typically required to maximize the electrical performance of a-IGZO TFTs, such high temperatures pose challenges for utilizing polymer substrates like plastics. Here, we thesis investigates the simultaneous lowtemperature plasma annealing process to develop next-generation high-performance flexible display devices. To define the optimal temperature, devices were fabricated and analyzed at varying temperatures of 40℃, 80℃, 120℃, and 160℃. Experimental results indicated that devices fabricated at 160℃ and 80℃ exhibited superior performance, with those at 160℃ demonstrating better performance in terms of current ratio, threshold voltage, and subthreshold swing. These findings confirm that the simultaneous low-temperature plasma annealing process is effective for next-generation high-performance displays.

High reliability thin film transistors are important factors for next-generation displays. The reliability of transparent a-IGZO semiconductors is being actively studied for display applications. A plasma treatment can fill the oxygen vacancies in the channel layer and the channel layer/insulating layer interface so that the device can work stably under a bias voltage. This paper studies the effect of plasma treatment on the performance of a-IGZO TFT devices. The influence of different plasma gases on the electrical parameters of device and its working reliability are reviewed. The article mentions argon, fluorine, hydrogen and several ways of processing in the atmosphere. Among these methods, F (fluorine) plasma treatment can maximize equipment reliability. It is expected that the presented results will form a basis for further research to improve the reliability of a-IGZO TFT.

In this study, we proposed an a-IGZO (amorphous In-Ga-Zn-O) TFT (thin-film transistor) with off-planed source/drain structure. Furthermore, two different electrode materials (ITO and Ti) were applied to the source and drain contacts for performance improvement of a-IGZO TFTs. When the ITO with a large work-function and the Ti with a small work-function are applied to drain electrode and source contact, respectively, the electrical performances of a-IGZO TFTs were improved; an increased driving current, a decreased leakage current, a high on-off current ratio, and a reduced subthreshold swing. As a result of gate bias stress test at various temperatures, the off-planed S/D a-IGZO TFTs showed a degradation mechanism due to electron trapping and both devices with ITO-drain or Ti-drain electrode revealed an equivalent instability.

In this study, we fabricate transparent and bendable a-IGZO (amorphous indium gallium zinc oxide) TFTs (thin-film transistors) with a-IZO (amorphous indium zinc oxide) transparent electrodes on plastic substrates and investigate their electrical characteristics under bending states. Our a-IGZO TFTs show a high transmittance of 82% at a wavelength of 550 nm. And these TFTs have an Ion/Ioff ratio of 1.8×108, a field effect mobility of 15.4 cm2/V·s, and a subthreshold swing of 186 mV/dec. The good electrical characteristics are retained even after bending with a curvature radius of 18 mm corresponding to a strain of 0.5% owing to mechanical durability of the transparent electrodes used in this study.

We have investigated the effect of electrical properties of amorphous InGaZnO thin filmtransistors (a-IGZO TFTs) by post thermal annealing in O2 ambient.The post-annealed in O2 ambienta-IGZOTFT is found to be more stable to be used for oxide-based TFT devices, and has betterperformance, such as the on/off current ratios, sub-threshold voltage gate swing, and, as well asreasonable threshold voltage, than others do. The interface trap density is controlled to achieve theoptimum value of TFT transfer and output characteristics. The device performance is significantlyaffected by adjusting the annealing condition. This effect is closely related with the modulation annealingmethod by reducing the localized trapping carriers and defect centers at the interface or in the channellayer.

Recently, amorphous oxide semiconductors (AOSs) based thin-film transistors (TFTs) have received considerable attention for application in the next generation displays industry. The research trends of AOSs based TFTs investigation have focused on the high device performance. The electrical properties of the TFTs are influenced by trap density. In particular, the threshold voltage (Vth) and subthreshold swing (SS) essentially depend on the semiconductor/gate-insulator interface trap. In this article, we investigated the effects of Ar plasma-treated SiO2 insulator on the interfacial property and the device performances of amorphous indium gallium zinc oxide (a-IGZO) TFTs. We report on the improvement in interfacial characteristics between a-IGZO channel layer and gate insulator depending on Ar power in plasma process, since the change of treatment power could result in different plasma damage on the interface.

Citations

• Effect of Ag Underlayer Thickness on the Electrical and Optical Properties of IGZO/Ag Layered Films
  So-Young Kim, Sun-Kyung Kim, Seung-Hong Kim, Jae-Hyun Jeon, Tae-Kyung Gong, Dong-Hyuk Choi, Dong-Il Son, Daeil Kim
  Journal of the Korean Society for Heat Treatment.2014; 27(5): 230.     CrossRef