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- 2018
- thin-film transistors
- N2O plasma treatment.
- amorphous InGaZnO
- gate-bias stress
- stability
- Electronic Science and Technology
- Peking University
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A method for alleviating the effect of pinhole defects in inter-metal dielectric films
摘要: As the insulation layers between two metal layers, inter-metal dielectric (IMD) films are widely used in integrated circuits (IC) and micro-electromechanical-systems (MEMS) devices. Commonly used IMD materials, such as silicon dioxide and silicon nitride, can be deposited on the metal surface using either physical vapor deposition (PVD) or chemical vapor deposition (CVD). However, due to the imperfections of deposition processes and surface cleanliness, defect-free of an IMD film cannot be guaranteed. As a common defect of an IMD film, pinhole is a tiny via of IMD film that can result in failures of short-circuit or current leakage between two metal layers and therefore decrease the fabrication yield. Reported methods for healing the pinhole defect require light-transmitting substrate, suspended structures, high-temperature annealing processes and none of them is universal. Therefore, we propose a metal etching method that uses metal etchants to etch the underlying metals through the pinholes of the IMD film. The etched area is reasonably larger than the pinhole; therefore, although the following upper metal deposition fills the pinhole, there is no electrical connection between the lower and upper metal features through the pinhole. Results of a series of experiments prove that the proposed method is feasible, valid, operable and reliable. Therefore, the proposed method is promising to be used for many IMD-based applications for either discovering pinholes or healing pinhole induced defects.
关键词: defect healing,thin film,inter-metal dielectric,pinhole,metal etching
更新于2025-09-23 15:23:52
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Layer-by-layer self-assembly of polyaniline nanofibers/TiO2 nanotubes heterojunction thin film for ammonia detection at room temperature
摘要: In this paper, for the first time, polyaniline nanofibers/TiO2 nanotubes (PANI/TiO2) heterojunction thin film has been prepared on Pt interdigital electrodes by layer-by-layer self-assembly method and applied in room temperature NH3 detection. It is found that the optimal self-assembly layer number is three (PANI/TiO2-3) compared to one layer (PANI/TiO2-1) and five layers (PANI/TiO2-5). The PANI/TiO2-3 thin film sensor possesses superior response characteristics compared with our other PANI based sensors, including higher response value (336%@5 ppm NH3), acceptable response/recovery time (110 s/1086 s@5 ppm NH3), low detection limit (0.5 ppm), and remarkable selectivity. The enhanced gas sensing performances could be ascribed to the tremendous variation of the carrier concentration caused by the p-n junctions as well as the increased specific surface area and pore volume. This work not only offers a superb strategy to fabricate heterojunction thin film but also accelerates the development of room-temperature operable NH3 sensors.
关键词: Ammonia detection,Layer-by-layer self-assembly,Polyaniline/TiO2 heterojunction,Thin film,Room temperature operation
更新于2025-09-23 15:23:52
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Hybrid bilayer gate dielectric-based organic thin film transistors
摘要: Organic thin film transistors (OTFTs) are key building blocks for flexible, low cost electronics systems. They provide a viable alternative for silicon-based electronics with added advantages of low cost and flexibility. However, few issues like high-operating voltage, low-switching speed, high-leakage current and reliability are still a challenge. The overall performance of an OTFT depends on organic semiconductors and gate dielectric interface. In this paper, we review the current status and trends in the choice of dielectric layer for OTFTs. As a starting point, the performance parameters of an OTFT and their dependence on the dielectric layer are briefly discussed. A variety of dielectric materials which includes high-k inorganic, organic, surface coated inorganics and nanocomposites are also presented. The advantages and drawbacks of each of these materials are discussed in detail. We reviewed the latest developments in the dielectric materials especially, self-assembled monolayers (SAMs), hybrid bilayers and nanocomposites. SAM-based OTFTs offer several advantages but shift in the threshold voltage remains a concern. Nanocomposites are a latest addition to the dielectric materials, which offer advantages like solution processing and improved dielectric constant but have a rough surface. A hybrid bilayer that incorporates the inorganic dielectric as a base layer and a thin polymer layer over it to improve the surface properties offers several desirable characteristics over the other choices. Hence, we propose that hybrid bilayer gate dielectrics shall play a pivotal role in improving the OTFT performance.
关键词: low-k organic,high-k inorganic,Organic thin film transistor,self-assembled monolayer,gate dielectric,hybrid bilayer
更新于2025-09-23 15:23:52
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Carbon Nanotube Thin Films for High-Performance Flexible Electronics Applications
摘要: Carbon nanotube thin films have attracted considerable attention because of their potential use in flexible/stretchable electronics applications, such as flexible displays and wearable health monitoring devices. Due to recent progress in the post-purification processes of carbon nanotubes, high-purity semiconducting carbon nanotubes can be obtained for thin-film transistor applications. One of the key challenges for the practical use of carbon nanotube thin-film transistors is the thin-film formation technology, which is required for achieving not only high performance but also uniform device characteristics. In this paper, after describing the fundamental thin-film formation techniques, we review the recent progress of thin-film formation technologies for carbon nanotube-based flexible electronics.
关键词: Flexible electronics,Carbon nanotube,Thin film
更新于2025-09-23 15:23:52
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Nano-rheology printing of sub-0.2 <i>μ</i> m channel length oxide thin-film transistors
摘要: Down-scaling of the channel length of a fully solution-processed oxide thin-film transistor (TFT) to the nanometer-scale is the key to accessing next-generation devices for Internet-of-Things technology. In this work, we report on the fabrication of an oxide TFT with a channel length of 160 nm, which is far less than those obtained by the current direct-printing techniques, by a newly developed nano-rheology printing (nRP) method. The device had an on/off current ratio, subthreshold voltage, hysteresis, and field-effect mobility of approximately 107, 1.7 V, 0 V, and 0.16 cm2 V s-1, respectively. The key to achieving the sub-micron channel printed TFT is the introduction of a new amorphous La–Ru–O material, which exhibits relatively good conductivity and excellent nRP properties at the nanoscale, for source/drain electrode patterns. Such a short-channel TFT would never be achieved with conventional printing methods, and hence, this approach is highly important for accessing next-generation low-cost, large-area and environmentally friendly printed electronics.
关键词: nano-rheology printing,thermal-imprinting,printed electronics,solution process,oxide thin-film transistor
更新于2025-09-23 15:23:52
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Photocatalytic oxidation of thiophene over cerium doped TiO2 thin film
摘要: Samples of TiO2 and TiO2 doped with 2% and 8% cerium ions were prepared by a sol-gel method and used as photocatalysts for the oxidation of vaporized thiophene. X-ray diffraction patterns showed a mixed phase of anatase and rutile for TiO2, while 2%Ce/TiO2 and 8%Ce/TiO2 were dominated by the anatase phase. As seen in the transmission electron microscopy image, the particle size of Ce/TiO2 was about 10 nm which was smaller than the undoped TiO2. The extended x-rays absorption fine structures revealed the substitutional effect of cerium in the TiO2 structure. Cerium-doped TiO2 exhibited a smaller photocurrent compared to that of TiO2, which suggested the electrons were trapped by cerium ions. In situ diffuse reflectance infrared spectroscopy under UV irradiation and x-ray photoemission spectroscopy were used to investigate the photocatalytic oxidation of thiophene on the prepared catalysts. Doping of cerium ions in TiO2 resulted in an enhanced adsorption of thiophene on the catalyst surface. The oxidation products of carboxylic acid with small amounts of sulfate ions were observed. As seen from the infrared absorption spectrum, 2%Ce/TiO2 and 8%Ce/TiO2 exhibited higher photocatalytic activity than those of the undoped TiO2.
关键词: Thiophene oxidation,Thin film,Cerium,Photocatalysis,Titanium dioxide
更新于2025-09-23 15:23:52
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Structural and Optical Properties of AlN/GaN and AlN/AlGaN/GaN thin films on Silicon Substrate prepared by Plasma Assisted Molecular Beam Epitaxy (MBE)
摘要: In this study, the Aluminium Nitride/Gallium Nitride (AlN/GaN) layers and Aluminium Nitride/Aluminium Gallium Nitride/Gallium Nitride (AlN/AlGaN/GaN) layer heterostructures were successfully created using technique known as plasma-assisted molecular beam epitaxy (MBE) on silicon substrate. Gallium (7N) and Aluminium (6N5) of high purity were used to grow GaN, AlN and AlGaN respectively. The structural and optical properties of the prepared AlN/GaN and AlN/AlGaN/GaN layer heterostructures were investigated by means of atomic force microscope (AFM), X-ray diffraction (XRD), photoluminescence spectroscopy (PL) and Raman spectroscopy. AFM measurement demonstrated that the root mean square of surface roughness for AlN/GaN and AlN/AlGaN/GaN heterostructures are 3.677 nm and 10.333 nm respectively. XRD data indicated that the samples have typical diffraction pattern of hexagonal structure. Raman spectra revealed all four Raman-active modes present inside both samples. PL spectra data showed the yellow luminescence which corresponds to the deep energy levels due to imperfections of AlN did not appear. Thus, PL observation indicated that the thin film of AlN/GaN and AlN/AlGaN/GaN layers have good optical quality and looks promising for various target applications in optoelectronics, photovoltaic and radiofrequency applications.
关键词: silicon,thin film,MBE,Aluminium Nitride,Gallium Nitride,Aluminium Gallium Nitride
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - A 300GHz Monolithic Integrated Amplifier in 0.5-μm InP Double Heterojunction Bipolar Transistor Technology
摘要: We present a compact, 6-stage terahertz monolithic integrated circuit (TMIC) amplifier with an operating frequency of 275-310GHz, formed by common-base configured 0.5 um InP Double Heterojunction Bipolar Transistor (DHBT) and a multilayer thin-film microstrip (TFM) wiring environment. The amplifier small signal gain exhibits >7.4dB at 300GHz. The peak gain is 12.5dB at 280GHz. This is the first time reported InP DHBT TMIC amplifier operating in H-band employing TFM in china. The total size of this 6-stage amplifier is only 1.7 mm ╳0.9 mm.
关键词: thin-film microstrip (TFM),Indium phosphide (InP),H-band,Amplifier,Heterojunction bipolar transistors (HBTs),Terahertz monolithic integrated circuit (TMIC)
更新于2025-09-23 15:22:29
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Complementary Integrated Circuits Based on n-Type and p-Type Oxide Semiconductors for Applications Beyond Flat-Panel Displays
摘要: Oxide semiconductors are highly attractive for fabrication of large-area thin-film electronics because of their high electrical performance, low process temperature, high uniformity, and ease of industrial manufacturing. n-type oxide semiconductors, such as InGaZnO, are highly developed and have already been commercialized for backplane drivers of flat-panel displays. To date, developing CMOS technology is still an urgent issue in order to build low-power electronic circuits based on oxide semiconductors. In this paper, various CMOS circuits, including inverters, NAND, NOR, XOR, d-latches, full adders, and 7-, 11-, 21-, and 51-stage ring oscillators (ROs), are fabricated based on sputtered p-type tin monoxide and n-type InGaZnO. The inverters show rail-to-rail output voltage behavior, low average static power consumption of 8.84 nW, high noise margin level up to ~40% supply voltage, high yield of 98%, and high uniformity with negligible standard deviation. The NAND, NOR, XOR, d-latches, and full adders show desirably ideal input–output characteristics. The performances of ROs indicate small stage delay of ~1 μs, extremely high uniformity and high yield which are essential for large-area thin-film electronics. This paper may inspire constructions of low power, large area, large scale, and high-performance transparent/flexible CMOS circuits fully based on oxide semiconductors for applications beyond flat-panel displays.
关键词: CMOS,oxide semiconductor,thin-film transistor (TFT),IC
更新于2025-09-23 15:22:29
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CuI Film Produced by Chemical Extraction Method in Different Media
摘要: CuI crystalline thin films were produced on substrates (commercial glass) using chemical extraction method in different chemical bath media. In this study, their structural, optical and electrical properties were analyzed. Transmittance, absorption, optical band gap and refractive index of the films were examined by UV/VIS spectrum. XRD data showed that the film has a hexagonal structure for CuI. Surface and elemental (in terms of ratio) analysis of the films were performed via SEM and EDX analysis. The highest average grain size of CuI was observed for the film produced in aqueous media whereas the lowest average grain size was seen in chloroform bath. The curve formed by the number of crystallites per unit area (N) is different than the curves of dislocation density and average grain size. Number of crystallites per unit area has reached its maximum value in CCl4 bath, but it has been decreased in chloroform bath. In addition, film thickness has varied between 1232 nm and 3624 nm according to the solvent of bath.
关键词: CuI films,Thin film,Chrystal growth,Optical properties
更新于2025-09-23 15:22:29