An organic light-emitting diode (OLED) display is disclosed. In one aspect, the display includes a stretchable substrate, a thin film transistor (TFT) formed over the stretchable substrate and including a plurality of electrodes, an OLED electrically connected to the TFT and including a plurality of electrodes, and a plurality of interconnection lines connected to the electrodes of the OLED and the TFT. At least one of the interconnection lines is configured to move in a stretching direction and rotate an electrode selected from the electrodes of the OLED and the TFT connected to the at least one interconnection line.

Organic light-emitting diode display

Two-dimensional (2D) materials have generated great interest in the past few years as a new toolbox for electronics. This family of materials includes, among others, metallic graphene, semiconducting transition metal dichalcogenides (such as MoS2), and insulating boron nitride. These materials and their heterostructures offer excellent mechanical flexibility, optical transparency, and favorable transport properties for realizing electronic, sensing, and optical systems on arbitrary surfaces. In this paper, we demonstrate a novel technology for constructing large-scale electronic systems based on graphene/molybdenum disulfide (MoS2) heterostructures grown by chemical vapor deposition. We have fabricated high-performance devices and circuits based on this heterostructure, where MoS2 is used as the transistor channel and graphene as contact electrodes and circuit interconnects. We provide a systematic comparison of the graphene/MoS2 heterojunction contact to more traditional MoS2-metal junctions, as well as a theoretical investigation, using density functional theory, of the origin of the Schottky barrier height. The tunability of the graphene work function with electrostatic doping significantly improves the ohmic contact to MoS2. These high-performance large-scale devices and circuits based on this 2D heterostructure pave the way for practical flexible transparent electronics.

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Graphene-MoS2 Hybrid Technology for Large-Scale Two-Dimensional Electronics

© 2020 The Author(s). We present an overview of the main techniques for production and processing of graphene and related materials (GRMs), as well as the key characterization procedures. We adopt a 'hands-on' approach, providing practical details and procedures as derived from literature as well as from the authors' experience, in order to enable the reader to reproduce the results. Section I is devoted to 'bottom up' approaches, whereby individual constituents are pieced together into more complex structures. We consider graphene nanoribbons (GNRs) produced either by solution processing or by on-surface synthesis in ultra high vacuum (UHV), as well carbon nanomembranes (CNM). Production of a variety of GNRs with tailored band gaps and edge shapes is now possible. CNMs can be tuned in terms of porosity, crystallinity and electronic behaviour. Section II covers 'top down' techniques. These rely on breaking down of a layered precursor, in the graphene case usually natural crystals like graphite or artificially synthesized materials, such as highly oriented pyrolythic graphite, monolayers or few layers (FL) flakes. The main focus of this section is on various exfoliation techniques in a liquid media, either intercalation or liquid phase exfoliation (LPE). The choice of precursor, exfoliation method, medium as well as the control of parameters such as time or temperature are crucial. A definite choice of parameters and conditions yields a particular material with specific properties that makes it more suitable for a targeted application. We cover protocols for the graphitic precursors to graphene oxide (GO). This is an important material for a range of applications in biomedicine, energy storage, nanocomposites, etc. Hummers' and modified Hummers' methods are used to make GO that subsequently can be reduced to obtain reduced graphene oxide (RGO) with a variety of strategies. GO flakes are also employed to prepare three-dimensional (3d) low density structures, such as sponges, foams, hydro- or aerogels. The assembly of flakes into 3d structures can provide improved mechanical properties. Aerogels with a highly open structure, with interconnected hierarchical pores, can enhance the accessibility to the whole surface area, as relevant for a number of applications, such as energy storage. The main recipes to yield graphite intercalation compounds (GICs) are also discussed. GICs are suitable precursors for covalent functionalization of graphene, but can also be used for the synthesis of uncharged graphene in solution. Degradation of the molecules intercalated in GICs can be triggered by high temperature treatment or microwave irradiation, creating a gas pressure surge in graphite and exfoliation. Electrochemical exfoliation by applying a voltage in an electrolyte to a graphite electrode can be tuned by varying precursors, electrolytes and potential. Graphite electrodes can be either negatively or positively intercalated to obtain GICs that are subsequently exfoliated. We also discuss the materials that can be amenable to exfoliation, by employing a theoretical data-mining approach. The exfoliation of LMs usually results in a heterogeneous dispersion of flakes with different lateral size and thickness. This is a critical bottleneck for applications, and hinders the full exploitation of GRMs produced by solution processing. The establishment of procedures to control the morphological properties of exfoliated GRMs, which also need to be industrially scalable, is one of the key needs. Section III deals with the processing of flakes. (Ultra)centrifugation techniques have thus far been the most investigated to sort GRMs following ultrasonication, shear mixing, ball milling, microfluidization, and wet-jet milling. It allows sorting by size and thickness. Inks formulated from GRM dispersions can be printed using a number of processes, from inkjet to screen printing. Each technique has specific rheological requirements, as well as geometrical constraints. The solvent choice is critical, not only for the GRM stability, but also in terms of optimizing printing on different substrates, such as glass, Si, plastic, paper, etc, all with different surface energies. Chemical modifications of such substrates is also a key step. Sections IV-VII are devoted to the growth of GRMs on various substrates and their processing after growth to place them on the surface of choice for specific applications. The substrate for graphene growth is a key determinant of the nature and quality of the resultant film. The lattice mismatch between graphene and substrate influences the resulting crystallinity. Growth on insulators, such as SiO2, typically results in films with small crystallites, whereas growth on the close-packed surfaces of metals yields highly crystalline films. Section IV outlines the growth of graphene on SiC substrates. This satisfies the requirements for electronic applications, with well-defined graphene-substrate interface, low trapped impurities and no need for transfer. It also allows graphene structures and devices to be measured directly on the growth substrate. The flatness of the substrate results in graphene with minimal strain and ripples on large areas, allowing spectroscopies and surface science to be performed. We also discuss the surface engineering by intercalation of the resulting graphene, its integration with Si-wafers and the production of nanostructures with the desired shape, with no need for patterning. Section V deals with chemical vapour deposition (CVD) onto various transition metals and on insulators. Growth on Ni results in graphitized polycrystalline films. While the thickness of these films can be optimized by controlling the deposition parameters, such as the type of hydrocarbon precursor and temperature, it is difficult to attain single layer graphene (SLG) across large areas, owing to the simultaneous nucleation/growth and solution/precipitation mechanisms. The differing characteristics of polycrystalline Ni films facilitate the growth of graphitic layers at different rates, resulting in regions with differing numbers of graphitic layers. High-quality films can be grown on Cu. Cu is available in a variety of shapes and forms, such as foils, bulks, foams, thin films on other materials and powders, making it attractive for industrial production of large area graphene films. The push to use CVD graphene in applications has also triggered a research line for the direct growth on insulators. The quality of the resulting films is lower than possible to date on metals, but enough, in terms of transmittance and resistivity, for many applications as described in section V. Transfer technologies are the focus of section VI. CVD synthesis of graphene on metals and bottom up molecular approaches require SLG to be transferred to the final target substrates. To have technological impact, the advances in production of high-quality large-area CVD graphene must be commensurate with those on transfer and placement on the final substrates. This is a prerequisite for most applications, such as touch panels, anticorrosion coatings, transparent electrodes and gas sensors etc. New strategies have improved the transferred graphene quality, making CVD graphene a feasible option for CMOS foundries. Methods based on complete etching of the metal substrate in suitable etchants, typically iron chloride, ammonium persulfate, or hydrogen chloride although reliable, are time- and resourceconsuming, with damage to graphene and production of metal and etchant residues. Electrochemical delamination in a low-concentration aqueous solution is an alternative. In this case metallic substrates can be reused. Dry transfer is less detrimental for the SLG quality, enabling a deterministic transfer. There is a large range of layered materials (LMs) beyond graphite. Only few of them have been already exfoliated and fully characterized. Section VII deals with the growth of some of these materials. Amongst them, h-BN, transition metal tri- and di-chalcogenides are of paramount importance. The growth of h-BN is at present considered essential for the development of graphene in (opto) electronic applications, as h-BN is ideal as capping layer or substrate. The interesting optical and electronic properties of TMDs also require the development of scalable methods for their production. Large scale growth using chemical/physical vapour deposition or thermal assisted conversion has been thus far limited to a small set, such as h-BN or some TMDs. Heterostructures could also be directly grown.

Production and processing of graphene and related materials

An object is to provide a method for manufacturing a semiconductor device, in which the number of photolithography steps can be reduced, the manufacturing process can be simplified, and manufacturing can be performed with high yield at low cost A method for manufacturing a semiconductor device includes the following steps: forming a semiconductor film; irradiating a laser beam by passing the laser beam through a photomask including a shield for shielding the laser beam; subliming a region which has been irradiated with the laser beam through a region in which the shield is not formed in the photomask in the semiconductor film; forming an island-shaped semiconductor film in such a way that a region which is not irradiated with the laser beam is not sublimed because it is a region in which the shield is formed in the photomask; forming a first electrode which is one of a source electrode and a drain electrode and a second electrode which is the other one of the source electrode and the drain electrode; forming a gate insulating film; and forming a gate electrode over the gate insulating film

Method for Manufacturing Semiconductor Device

A method for growing films for use in integrated circuits using atomic layer deposition and a subsequent converting step is described. In an embodiment, the subsequent converting step includes oxidizing a metal atomic layer to form a metal oxide layer. The atomic layer deposition and oxidation step are then repeated to produce a metal oxide layer having sufficient thickness for use as a metal oxide layer in an integrated circuit. The subsequent converting step, in an embodiment, includes converting the atomic deposition layer by exposing it to one of nitrogen to form a nitride layer, carbon to form a carbide layer, boron to form a boride layer, and fluorine to form a fluoride layer. Systems and devices for performing the method, semiconductor devices so produced, and machine readable media containing the method are also described.

Atomic layer deposition and conversion

Transistors, and methods of manufacturing the transistors, include graphene and a material converted from graphene. The transistor may include a channel layer including graphene and a gate insulating layer including a material converted from graphene. The material converted from the graphene may be fluorinated graphene. The channel layer may include a patterned graphene region. The patterned graphene region may be defined by a region converted from graphene. A gate of the transistor may include graphene.

Transistors and methods of manufacturing the same

An ink-jet printhead and a method of manufacturing the same include a substrate on which a heater and a passivation layer protecting the heater are formed, a passage plate on which an ink chamber corresponding to the heater and an ink passage connected to the ink chamber are formed, and a nozzle plate in which an orifice corresponding to the ink chamber is formed. An exposure stop layer (ESL) that blocks passage of a photosensitive energy is formed inside the nozzle plate, and the nozzle plate and the passage plate are bonded with each other by the exposure stop layer (ESL).

Monolithic ink-jet printhead and method for manufacturing the same

A bubble-jet type ink-jet printhead, and a manufacturing method thereof are provided, wherein, the printhead includes a substrate integrally having an ink supply manifold, an ink chamber, and an ink channel, a nozzle plate having a nozzle, a heater consisting of resistive heating elements, and an electrode for applying current to the heater. In particular, the ink chamber is formed in a substantially hemispherical shape on a surface of the substrate, a manifold is formed from its bottom side toward the ink chamber, and the ink channel linking the manifold and the ink chamber is formed at the bottom of the ink chamber. Thus, this simplifies the manufacturing process and facilitates high integration and high volume production. Furthermore, a doughnut-shaped bubble is formed to eject ink in the printhead, thereby preventing a back flow of ink as well as formation of satellite droplets that may degrade image resolution.

Bubble-jet type ink-jet printhead and manufacturing method thereof

We demonstrate herein an effective method of forming a high-quality contact between metal and graphene on a wafer as large as 6 in. This gold-assisted transfer method producing no polymer residue on the graphene surface is introduced, and then the gold film is used directly as an electrode to form the transfer length method pattern for calculating the contact resistance. The graphene surface obtained using the gold-assisted transfer method is clean and uniform without residue or contamination, and its contact resistance is at least 60% lower than that obtained using the conventional poly(methyl methacrylate) assisted transfer method.

Clean transfer of graphene and its effect on contact resistance

In this paper, we have successfully fabricated and characterized self-aligned TaN and TaN/poly-Si gated n-MOSFETs with ultra thin (EOT=11 /spl Aring/) CVD ZrO/sub 2/ gate dielectrics. It is show that while both gate stacks show excellent leakage current and good thermal stability after a 900/spl deg/C, 30 s, N/sub 2/ anneal, the TaN/poly-Si ZrO/sub 2/ devices exhibit superior thermal stability even after 1000/spl deg/C, 30 s, N/sub 2/ anneal. In addition, the TaN/poly-Si devices show negligible frequency dependence of CV, charge trapping, and superior TDDB characteristics, compared to TaN devices. Well-behaved N-MOSFETs with both TaN and TaN/poly-Si gate electrodes are demonstrated.

https://www.vlsisymposium.org/Past/01web/technology/tec_pdf/T11p4.pdf

Chang-seung Lee

Papers

Transistors and methods of manufacturing the same

Monolithic ink-jet printhead and method for manufacturing the same

Bubble-jet type ink-jet printhead and manufacturing method thereof

Clean transfer of graphene and its effect on contact resistance

MOS devices with high quality ultra thin CVD ZrO/sub 2/ gate dielectrics and self-aligned TaN and TaN/poly-Si gate electrodes