High‐Performance Solution‐Processed IGZO Thin‐Film Transistors with Al₂O₃/BN Composite Dielectrics Fabricated at Low Temperature

Abstract

Recently, solution-process technologies have attracted significant amounts of attention with regard to fabrication costs, and capable of large-area deposition for various electronic devices and circuitry. In particular, solutionprocessed composite dielectrics have been thoroughly investigated in an effort to improve device performance of thin-film transistors (TFTs). Here, solution-processed indium-gallium-zinc-oxide (IGZO) TFTs with solutionprocessed aluminum oxide (Al 2 O 3 ) and boron nitride (BN) composite films are reported which can be fabricated at low temperature. By optimizing the process conditions of Al 2 O 3 /BN composite dielectrics, the field-effect mobility of an IGZO TFT is increased by a factor of 3, relative to that of pristine Al 2 O 3 dielectrics. This is a result of the improved dielectric characteristics of solution-processed Al 2 O 3 films owing to the reduced density of the defect states. Characterization using transmittance, X-ray photoelectron spectroscopy and direct-current electrical measurements conclusively demonstrate that IGZO-TFTs fabricated with energy electronically excited by microwave absorption exhibit competitive device performance with those fabricated with energy thermally activated by thermal heating at 400 C.

Explaining Bamboo-Like Carbon Fiber Growth Mechanism: Catalyst Shape Adjustments above Tammann Temperature

“…Recently, carbon CB and CN thin films have been produced exhibiting interesting properties [67,68]. The atomic structure of CN, CN and BN films is shown in Figure 8 [64].…”

Ultralow Voltage Driving Circuits Based on Coplanar a‐InGaZnO TFTs with Photopatternable Ionic Polymer Gate Dielectric

“…However, most a-InGaZnO TFTs reported so far with conventional gate dielectric materials (i.e., SiO 2 ) were operated at high operation voltages over 20 V to obtain high field-effect mobility and on-off ratios [11][12][13][14] because of the relatively low dielectric constant limiting the maximum accumulated carrier density (<10 13 cm −2 ). [15,16] To overcome these difficulties and realize the low-voltage operation, there have been many different approaches on developing new gate dielectrics, including high-dielectric constant (high-k) oxide materials, [17] hybrid multicomponent, [18] ionic liquid, [19] poly mer electrolyte, [20] and solid electrolyte. [21] Among these, the gate dielectric forming the electric double layer (EDL) using an ionic polymer, [22][23][24] comprising ionic liquids in a polymer matrix, has been extensively studied, thanks to its advantages of induced ultrahigh density carrier attainability in the channel, improved capacitive coupling, low-voltage operation, and lowtemperature fabrication process.…”

“…To overcome these difficulties and realize the low‐voltage operation, there have been many different approaches on developing new gate dielectrics, including high‐dielectric constant (high‐ k ) oxide materials, hybrid multicomponent, ionic liquid, polymer electrolyte, and solid electrolyte . Among these, the gate dielectric forming the electric double layer (EDL) using an ionic polymer, comprising ionic liquids in a polymer matrix, has been extensively studied, thanks to its advantages of induced ultrahigh density carrier attainability in the channel, improved capacitive coupling, low‐voltage operation, and low‐temperature fabrication process .…”

Large Area, Ultrathin, and Transparent InGaZnO Films from Printing of Liquid Ga–In–Zn Alloys for Thin Film Transistors

“…Up to now, vacuum deposition and liquid solution deposition have been widely used to grow IGZO films. − Though the high crystallization and uniformity IGZO films can be harvested by using the vacuum deposition process, the high vacuum atmosphere, experimental equipment, and uniform IGZO targets are the main challenges of obtaining low-cost IGZO films. Using a liquid solution deposition process to produce IGZO films drew much attention in recent years, because of the low cost and large area IGZO films can be easily harvested by using this facile synthesis technology. − Though the method of liquid solution deposition can realize the preparation of IGZO films in an air atmosphere, the unavoidable hole defects on the surface of IGZO films and the high annealing temperature for IGZO films’ crystallization are challenging problems in obtaining high-quality IGZO films at low temperatures. Additionally, it is hard to obtain two-dimensional (2D) or ultrathin IGZO films using the aforementioned process.…”