High-Quality Solution-Processed Silicon Oxide Gate Dielectric Applied on Indium Oxide Based Thin-Film Transistors

Abstract

A silicon oxide gate dielectric was synthesized by a facile sol-gel reaction and applied to solution-processed indium oxide based thin-film transistors (TFTs). The SiOx sol-gel was spin-coated on highly doped silicon substrates and converted to a dense dielectric film with a smooth surface at a maximum processing temperature of T = 350 °C. The synthesis was systematically improved, so that the solution-processed silicon oxide finally achieved comparable break downfield strength (7 MV/cm) and leakage current densities (<10 nA/cm(2) at 1 MV/cm) to thermally grown silicon dioxide (SiO2). The good quality of the dielectric layer was successfully proven in bottom-gate, bottom-contact metal oxide TFTs and compared to reference TFTs with thermally grown SiO2. Both transistor types have field-effect mobility values as high as 28 cm(2)/(Vs) with an on/off current ratio of 10(8), subthreshold swings of 0.30 and 0.37 V/dec, respectively, and a threshold voltage close to zero. The good device performance could be attributed to the smooth dielectric/semiconductor interface and low interface trap density. Thus, the sol-gel-derived SiO2 is a promising candidate for a high-quality dielectric layer on many substrates and high-performance large-area applications.

Femtosecond laser patterning of graphene electrodes for thin-film transistors

“…This corresponds to a maximum interface trap density N S of 3.4×10 12 cm −2 and 2.0×10 12 cm −2 of the TFTs with graphene electrodes patterned in air and in vacuum, respectively. These values are higher compared to MOTFTs based on the same precursor with metal electrodes patterned by conventional lift-off technique (S sub = 0.37 V/dec) [34]. We attribute this to a rough semiconductor/insulator interface arising from the debris.…”

“…Thicker MO films result in the presence of a highconductive back-channel layer at a distance beyond the screening length of the metal oxide/dielectric stack that induces humplike subthreshold transfer characteristics and more negative threshold voltages [38,39]. Additionally, the variations in film thickness might cause an incomplete conversion of the MO precursor, since the conversion parameters are optimized for a homogeneous layer [34,40]. These effects lead to a parasitic conductivity causing the measured hysteresis and lacking saturation.…”

Facile Synthesis of Solution-Processed Silica and Polyvinyl Phenol Hybrid Dielectric for Flexible Organic Transistors

“…Solution-processed metal oxide semiconductors have made enormous progress in the past few years [8][9][10]. However, the film prepared by the solution method has the general problem of a large leakage current, especially for the silica film prepared by solution-gelation (sol-gel) [11,12]. Due to the holes or pores generated during film preparation, the switching current of related devices is relatively low at present.…”

Scalability and homogeneity of slot die‐coated metal oxide semiconductor for TFTs

“…In order to fulfill these demands, the specialty chemical company Evonik Resource Efficiency GmbH (Evonik) has developed an indium oxide-based precursor solution that can be applied in ambient conditions by coating with high mobility and a uniform layer even on large-area substrates. 9,10 The low processing temperatures of this new material can enable the development of flexible displays. 11 To realize this promise in mass production, Evonik as a material maker is cooperating with equipment maker SCREEN Finetech Solutions Co., Ltd. (SCREEN FT) who has proven know-how and experience of slot die coating technology to develop mass production equipment and high coating technology in the field of flat panel display.…”

“…In order to fulfill these demands, the specialty chemical company Evonik Resource Efficiency GmbH (Evonik) has developed an indium oxide‐based precursor solution that can be applied in ambient conditions by coating with high mobility and a uniform layer even on large‐area substrates . The low processing temperatures of this new material can enable the development of flexible displays .…”