Printed, Highly Stable Metal Oxide Thin‐Film Transistors with Ultra‐Thin High‐κ Oxide Dielectric

Abstract

Lately, printed oxide electronics have advanced in the performance and low‐temperature solution processability that are required for the dawn of low‐cost flexible applications. However, some of the remaining limitations need to be surpassed without compromising the device electronic performance and operational stability. The printing of a highly stable ultra‐thin high‐κ aluminum‐oxide dielectric with a high‐throughput (50 m min−1) flexographic printing is accomplished while simultaneously demonstrating low‐temperature processing (≤200 °C). Thermal annealing is combined with low‐wavelength far‐ultraviolet exposure and the electrical, chemical, and morphological properties of the printed dielectric films are studied. The high‐κ dielectric exhibits a very low leakage‐current density (10−10 A cm−2) at 1 MV cm−1, a breakdown field higher than 1.75 MV cm−1, and a dielectric constant of 8.2 (at 1 Hz frequency). Printed indium oxide transistors are fabricated using the optimized dielectric and they achieve a mobility up to 2.83 ± 0.59 cm2 V−1 s−1, a subthreshold slope <80 mV dec−1, and a current ON/OFF ratio >106. The flexible devices reveal enhanced operational stability with a negligible shift in the electrical parameters after ageing, bias, and bending stresses. The present work lifts printed oxide thin film transistors a step closer to the flexible applications of future electronics.

The 2021 flexible and printed electronics roadmap

“…Backplanes are fabricated on a thin polyimide film released from a glass carrier after processing, giving equivalent TFT performance to those deposited on glass. A-Si and IGZO can be deposited below 200 • C with minor reduction in performance making them accessible to other plastic substrates [34], and IGZO can be printed from a sol-gel solution with annealing at about 400 • C. IGZO flexible microprocessors have been demonstrated [35].…”

Printable Organic‐Inorganic Nanoscale Multilayer Gate Dielectrics for Thin‐Film Transistors Enabled by a Polymeric Organic Interlayer

“…Among the several promising high-k materials reported in the literature, most using metal oxides, [7,[19][20][21] this laboratory invented a family of robust, structurally well-defined selfassembled nanodielectrics (SANDs), which not only have relatively high dielectric constants (κ org. ≈ 7) and high-breakdown thresholds (E BD ≈ 6 MV cm −1 ), but also thicknesses below 20 nm, thus affording high capacitance values combined with facile fabrication by solution-processing, and broad compatibility with diverse semiconductor families.…”

Recent Progress in Solution‐Based Metal Oxide Resistive Switching Devices

“…To overcome this issue, UV photochemical techniques have been explored as a viable option due to their compatibility with printed electronic industry, offering high quality materials at a reduced associated cost and process time. [96,230] Yang and coworkers studied the use of a UV-based (KrF, 248 nm) excimer laser annealing to produce solution-based NiO thin films and their application in RRAMs. [229] Specific areas of these films were exposed to the laser irradiation for only 3 min, resulting in the production NiO RRAMs with a resistance window of 10 3 , as shown in Figure 13b.…”