Wavy Architecture Thin‐Film Transistor for Ultrahigh Resolution Flexible Displays

Abstract

pixel receives a charge, through a driving TFT, and thus no interference comes from neighboring pixels. [3] As a result, the resolution of active-matrix-based displays can be dramatically increased in comparison with passive matrix displays. The current market dominant product of full high definition AM-LCDs has pixel numbers around three millions (1920 × 1080 × 3(RGB)). [4] Future 8K displays are expected to have more than 33.2 megapixels (4320 × 7680 × 3(RGB)), more than 300 Pixels Per Inch (PPI), and a fast frame rate (>240 Hz) in order to suppress the motion blur effect at such high resolution. [5] The essential requisite for achieving these features is a high fieldeffect mobility, µ, in TFTs. For example, 8K displays switching at 240 Hz frame rate demand field-effect mobility around 10-20 cm 2 (V s) −1 , and even higher values are desired for future displays. [6] This is because a higher µ induces a higher drain current, thus enabling the TFTs to switch faster and/or occupy a smaller pixel area. A typical current-controlled active-matrix circuit, which controls individual OLED or LCD pixels, has four TFTs and two capacitors. [3,7,8] Thus, a smaller TFT area is required for achieving both higher resolutions and higher pixel fill factor, which is defined as the ratio of the light emitting area over the total area of the pixel. Another important motivation for scaling TFT sizes is that the allowed pixel size decreases as the number of PPI increases, which is critical for future high resolution mobile applications such as the use of flexible displays for point-of-care medical diagnostic testing. [9] For example, the pixel size for 500 PPI is only 50.8 × 16:9 µm 2 . [4] Hence, it is imperative that the TFT size be scaled down along with the pixel size to be fitted inside such a small pixel area.Amorphous Oxide Semiconductors have been excellent TFT channel material candidates for future large-area FPD since their typical field-effect mobility values for n-type oxides have been in the range of 10 cm 2 (V s) −1 for indium gallium zinc oxide (InGaZnO-or popularly IGZO)-based devices, and 20 cm 2 (V s) −1 for indium (In) rich films, which are within the required range for future 8K displays. [10] However, in order to reduce the area occupied by TFT circuitry, gate length scaling has been the traditional route of downsizing TFT area. [11][12][13] Various studies have been conducted to study gate length scaling effects on n-type oxides such as ZnO, [14] InGaZnO, [4,15] A novel wavy-shaped thin-film-transistor (

P‐19: IGZO Thin‐Film Transistors on Corrugated Substrate for High‐Resolution Display

“…In another approach, a corrugated structure was utilized to increase the channel width; however, an additional layer, different from the substrate, was required to make corrugations. This additional process increases process complexity and cost [5]. In this work, we propose a method to increase the TFT drain current by patterning the substrate directly into a corrugated structure.…”

Layer-Scale and Chip-Scale Transfer Techniques for Functional Devices and Systems: A Review

“…The development of flexible or wearable devices is another major factor driving the need for developing cost-effective layer transfer and chip transfer techniques [ 124 , 129 , 136 , 137 , 138 , 139 , 140 , 141 , 142 , 143 , 144 ]. Flexible electronics can find a wide range of applications, such as flexible or stretchable displays [ 137 , 145 , 146 , 147 , 148 , 149 , 150 , 151 , 152 , 153 ], flexible transistors [ 154 , 155 , 156 , 157 , 158 , 159 , 160 ], flexible solar cells [ 77 , 92 , 161 ], flexible sensors [ 162 , 163 , 164 , 165 , 166 ], wearable medical devices [ 127 , 167 , 168 , 169 ], and human–machine interfaces [ 170 , 171 , 172 , 173 , 174 ]. While organic semiconductors are naturally suited for fabricating flexible devices because of their solution processable and conformal coating compatibility with the flexible substrate,...…”

Oxide semiconductor thin-film transistors with nano-splitting and field-surrounding channels fabricated by subwavelength photolithography

“…Nowadays, the pattern methods have been reported in nano-or micro-structures transistors are conventional lithography [17,22,23], electron beam lithography [19], nanoimprint lithography [18,21,24], lithographically controlled wetting [20,25], etc. However, these technologies have their shortcomings in resolution, cost of facility, application, and repeatability.…”