Flexible, Transparent, High Mobility Amorphous In–Ga–Zn-O Thin Film Transistors Fabricated on Textile

Abstract

To implement wearable textile displays (WTDs), it is essential that unique properties such as physical and chemical properties, aesthetics, and flexibility of the textile be maintained. Therefore, thin film transistors (TFTs) for WTDs should exhibit excellent electrical properties to enable 4K and 8K high resolution and high frame-rate (>120 Hz) displays while maintaining the properties of textiles. All layers of TFTs were formed by vacuum deposition and oxide-based transparent materials; amorphous In–Ga–Zn-O (a-IGZO), indium tin oxide (ITO), and Al2O3 were used. A transparent and flexible electrode with an ITO/Ag/ITO (IAI) structure was optimized and applied to the source/drain and gate. All processes were performed below 150 °C, and the wet-step was eliminated to prevent physical and chemical deformation of the substrate. The flexible, transparent, high mobility a-IGZO TFTs (FTH TFTs) for WTDs were fabricated on glass, polyethylene terephthalate (PET) film, and textile substrates, respectively. Their electrical performance, transparency, and flexibility were then compared. The textile-based TFTs showed transmittance of 72.98%, high mobility of 11.5 cm2/(V s), and an on/off ratio of 9.28 × 107 even in a low temperature process (<150 °C). In addition, the electrical properties of the textile-based TFTs were maintained despite testing entailing 1000 cycles of bending with a tensile strain of 0.8%. In particular, the FTH TFTs for WTDs were able to stably drive a red organic light-emitting diode on textile.

Channel Nanoscaling of InGaZnO TFTs and Circuits via Focused Ion Beam

“…1 This is only possible thanks to the suitability of current semiconductor manufacturing technologies on various types of substrates, 2,3 which guarantee the possibility of realizing epidermal systems, 4,5 foldable displays, 6 and electric textiles. 7,8 Among the semiconductor technologies, such as organic, 9,10 2-D, 11,12 and metal oxide semiconducting 13,14 materials, the latter, and in particular indium gallium zinc oxide (IGZO), provide the best trade-off between large-area fabrication, low-temperature manufacturing, and electrical performance. 15,16 However, the carrier mobility of IGZO thin-film transistors (TFTs), typically around 10 cm 2 V −1 s −1 when fabricated at room temperature, 17 still remains a limitation in the development of fast thin-film devices for data transmission and communications.…”

“…Thin-film electronics on flexible substrates yield unprecedented and unique properties, enabling the realization of lightweight and bendable systems . This is only possible thanks to the suitability of current semiconductor manufacturing technologies on various types of substrates, , which guarantee the possibility of realizing epidermal systems, , foldable displays, and electric textiles. , Among the semiconductor technologies, such as organic, , 2-D, , and metal oxide semiconducting , materials, the latter, and in particular indium gallium zinc oxide (IGZO), provide the best trade-off between large-area fabrication, low-temperature manufacturing, and electrical performance. , However, the carrier mobility of IGZO thin-film transistors (TFTs), typically around 10 cm 2 V –1 s –1 when fabricated at room temperature, still remains a limitation in the development of fast thin-film devices for data transmission and communications. Furthermore, while 40 nm-long IGZO TFTs were demonstrated when fabricated on a rigid substrate, the best achievable resolution of standard lithographic processes is restricted by the use of free-standing flexible polymeric substrates and, mainly, by their thermal expansion during the manufacturing process .…”

Enhanced Electrical Properties and Stability in IGZO TFTs via Low-Temperature Activation with MgOx Layer

“…Amorphous oxide semiconductor thin-film transistors (TFTs) are extensively examined for display backplanes owing to their high field effect mobility (μ FE ; > 10 cm 2 /(V s)), high transparency to visible light, and low off-current (<100 pA), compared with hydrogenated amorphous silicon TFTs. , Especially, IGZO TFTs fabricated through sputtering have shown promise as switching devices and have achieved successful commercialization in display backplanes. Since 2012, IGZO TFTs have found application in large-area flat-panel display backplanes for commercial products, including organic light-emitting diode displays and liquid crystal displays. − Moreover, since 2018, IGZO TFTs have increasingly emerged in small- to medium-sized flat-panel display panels, incorporating low-temperature polycrystalline silicon and oxide (LTPO) technology. This technology utilizes the low off-current of oxide TFTs to support frame rates of 120 Hz for fast-motion images while also adopting frame rates of 1 Hz for low-motion images to reduce power consumption.…”

Effect of Tunable Sub-Source and Sub-Drain Device Behavior in Four-Terminal Operation Using Metal-Capping Thin-Film Transistors

“…These materials were first developed by Hosono’s group in 2004 and have since garnered considerable research attention . Research on the application of AOSs in transparent displays, functional devices on flexible substrates, various sensors, neuromorphic devices, photodetectors, and other electronic devices has demonstrated promise for future electronic devices. TFTs based on AOSs are extensively studied for their good characteristics and integration capability through various structures. − To apply TFTs based on AOSs with various structures to next-generation applications, it is crucial to conduct research on their mechanism analysis and characterization.…”