Organic thin film transistor integration a hybrid approach,best vegetables to plant in spring in texas,raised garden bed 2 tier - Step 3

Author: admin, 13.03.2015. Category: Organic Food

The blind fish have evolved sparse body hairs that are highly sensitive to the movement of water.
To date, the researchers have fabricated an array of eight microsensors and shown that the array is able to detect an oscillating object underwater.
German and French teams are combining EUR 14.5m investment into development of strained-silicon on insulator (sSOI) technology under the DEvice and CIrcuit performance boosted through SIlicon material Fabrication (DECISIF) program. These global strain techniques will be combined with new techniques to create locally strained silicon to reach an exceptionally high mobility of the charge carrier within transistors. Novaled, the provider of Organic Light Emitting Diode (OLED) technology and materials, and Holst Centre, an independent R&D centre developing generic technologies for Wireless Autonomous Transducer Solutions and for Systems-in-Foil, have decided to collaborate on the development of organic thin film transistor (OTFT) technologies under a joint development agreement.
Novaled’s doping technology contributes to very high power efficiencies and long lifetimes in OLEDs by improving charge carrier injection and transport in the organic layers. Gerwin Gelinck, Program Manager Organic Circuitry at Holst Centre, commented, “It is our strong believe that only through this type of collaboration, cutting edge processes and prototypes are developed that will accelerate introduction of organic transistor products to the market place. It is always sunrise somewhere on our spinning sphere, and the sun is always changing too (see figure). The guaranteed loan, expected to provide debt financing for approximately 73% of the project costs, will allow Solyndra to initiate construction of a second solar panel fabrication facility (Fab 2) in California. BetaSights recently visited Xactix in Pittsburgh, PA, and the MEMS OEM reports booming business for Xenon difluoride (XeF2) chemical vapor etch (CVE) systems. Keithley Instruments has been very busy extending the capabilities of it’s 4200-SCS (Semiconductor Characterization System) with new cables for IC measurements and new software libraries for PV, OLED, and other devices. The new triaxial cabling kits (see figure) are based on a patent-pending design that speeds and simplifies the process of making DC Current-Voltage (I-V), Capacitance-Voltage (C-V), and pulsed I-V testing connections.
The company has introduced other hardware, firmware, and software enhancements to the 4200-SCS. The new test libraries expand capabilities for solar cell I-V, C-V, and resistivity testing applications, and also supports Drive-Level Capacitance Profiling (DLCP). Novellus’ applications labs have been working on CVD low-k dielectrics targeting 32nm node multilevel metal specs, and the result is “dense” ultra-low-k (ULK) film with bulk k=2.5 and the potential to go lower. Despite mis-directions from early editions of the ITRS, in which a new low-k material was supposed to be integrated into production for each new node, the world has mostly settled on the use of CVD SIOC(H) for k~3 films. The company’s “dense” ULK film is reportedly deposited as a single phase from a single precursor, instead of the two precursors used for PLK deposition. Mentor Graphics has announced new capabilities to the Calibre(R) platform to allow designers to control thickness variability due to Chemical Mechanical Planarization (CMP) at advanced process nodes. Variations in thickness created by chemical-mechanical processing (CMP) can lead to manufacturing and parametric performance issues.
Both AMD and CSR have already used SmartFill; CSR was able to successfully tape-out a RFCMOS 65nm design and get first-time-right working chips from TSMC.
Wright Williams & Kelly (WWK), the cost and productivity modeling company, is now providing free general information in an electronic newsletter, and has lowered the cost to start using it’s flagship TWO COOL(R) cost of ownership (CoO) modeling software. The CoO and overall equipment efficiency (OEE) modeling software, now version 3 (see figure), is the de facto standard for fab industries, since it was derived from original SEMATECH CoO modeling work and is compliant with SEMI standard E35. This editor has been working productively with versions of this software since 1992, and used it to model the integration costs of different low-k dielectric technologies for a Materials Research Society presentation in 1997 (Session N3.10). There are many known integration challenges with PLK materials: material degradation during plasma etch, pore-sealing on sidewalls, compatibility with metal CMP processes, etc. In Session 26.7 of IEDM2008, NEC showed “damage-less” full Molecular Pore Stack (MPS) SiOCH intermetal dielectric integration including direct CMP.
The bulk MPS material is hydrophobic so that an aqueous process like CMP leaves water marks behind. The graphic shown in the March 5th post was a schematic of a TMV PoP using wire-bonded chips. Amkor’s motivation with TMV is to provide a low-risk path to extend PoP for it’s customers. Besides PoP and TSV, the other known 3D stacking solution is edge-contacts (see figure, shown by Tohoku University in Session 20.5 of IEDM 2008). Under the NEDO project, a group consisting of Tokyo University, Technology Institute of Osaka Prefecture and others developed an organic temperature sensor and high performing semiconductor digital circuit that can be manufactured using printing method. Organic semiconductor has following characteristics in comparison with inorganic semiconductor such as silicon. Although a film layer can be created easily and at low cost, in reality, it was difficult to achieve a high-speed response performance that meets the requirement of an RFID tag communication.
A group consisting of Tokyo University, Technology Research Institute of Osaka Prefecture and others developed an organic temperature sensor and high-performance semiconductor digital circuit that can be manufactured using printing method.
Based on the technology to coat and crystallize organic semiconductor, the group developed a unique organic digital temperature sensor that can be coated as a high performance organic CMOS circuit and succeeded in transmitting digital signal over a commercial radio frequency of 13.56MHz. A wide range of application can be expected using a low-cost electronic tag with sensor functionality that is light, thin, and bendable.
On January 28, 2015, at a€?nano tech 2015a€? to be held in Tokyo Bigsight, a demonstration to transmit RFID signal will be conducted.
By developing the technology indicated below, digital temperature sensor and the high-performance organic logic circuit can be produced using the printable method. In cooperation with FUJIFILM Corporation, processing on a flexible substrate has been considered and circuit movement has been successfully confirmed. Technology Research Institute of Osaka Prefecture found that the resistance of organic high molecule material PEDOT-PSS changes in accordance to the temperature. Printable organic digital circuit enabling digital conversion of the sensor output and signal transmission using RFID digital communication leads to the development of low cost, light weight, and flexible sensing device for NFC (near-filed communication). Professor Takeya (et al.) of Tokyo University developed a transistor using organic semiconductor crystal in 2003. Under the NEDO project, research and development towards practical implementation will be accelerated to build a prototype of RFID tag with temperature sensor for logistic management. Organic semiconductors offer great promise for large area, low-end, lightweight, and flexible electronics applications. While the material properties and processing technology for organic semiconductors continue to advance and mature, progress in organic thin film transistor (OTFT) integration and its scalability to large areas has not enjoyed the same pace. Most of the results presented here stem from research conducted at the Giga-to-Nano Labs, University of Waterloo, and the Xerox Research Centre of Canada (XRCC), which granted access to its high quality, high performance, stable organic semiconductor materials.
The text has evolved from a series of courses offered to graduate students in Electrical Engineering as well as doctoral dissertations covering different aspects of large area electronics. This book would not have been possible without the support of various institutions and funding agencies: University of Waterloo, Xerox Research Centre of Canada, University College London, University of Cambridge, Nanyang Technological University, Natural Sciences and Engineering Research Council of Canada, Ontario Centres of Excellence, and The Royal Society. Charge transfer complex (CT complex) An electron donora€“electron acceptor complex, characterized by electronic transition(s) to an excited state. Conductive polymer (also conducting polymer) Polymer that is made conducting, or a€?doped,a€? by reacting the conjugated semiconducting polymer with an oxidizing agent, a reducing agent, or a protonic acid, resulting in highly delocalized polycations or polyanions. Conjugated polymer A system of atoms covalently bonded with alternating single and double carbona€“carbon (sometimes carbona€“nitrogen) bonds in a molecule of an organic compound. Mobility (also carrier mobility, field-effect mobility, effective mobility) The state of being in motion. Organic compounds Chemical compounds containing carbon-hydrogen (Ca€“H) bonds of covalent character. Organic electronics (also plastic electronics) A branch of electronics that deals with conductive polymers, plastics, or small molecules. Organic semiconductor (also polymer semiconductor) Any organic material that has semiconductor properties.
OTFT (also OFET) An organic thin film transistor (OTFT) or organic field effect transistor (OFET) is a field effect transistor using an organic semiconductor in its channel. Plastic A general term for a wide range of synthetic or semi-synthetic polymerization products. Polymer A substance composed of molecules with large molecular mass composed of repeating structural units, or monomers, connected by covalent chemical bonds. Organic semiconductor technology has attracted considerable research interest in view of its great promise for large area, low-end, lightweight, and flexible electronics applications [1]. The transistor is a fundamental building block for all modern electronics; transistors based on organic semiconductors as the active layer are referred to as organic thin film transistors (OTFTs).
The unique features which give organic electronics a technological edge are simpler fabrication methods and the ability to mechanically flex.
Historically, organic materials (or plastics) were viewed as insulators, with applications commonly seen in inactive packaging, coating, containers, moldings, and so on. The continued evolution of organic semiconductor materials from the standpoint of electrical stability, processability, functionality, and performance is enabling realization of high-performance devices in laboratory environments [10a€“14]. The outlook for low-cost production of organic electronics is a key driver for market opportunities in this area. Illustration of cost versus performance comparison of silicon technology and organic semiconductor technology. One of the most frequently discussed opportunities for organic electronics is their integration as the driver backplane of flexible displays.
The application of OTFTs for large area displays has been demonstrated by a number of companies and research institutions. A number of corporations have also invested in R&D for OTFT-driven large area displays.
The mechanical flexibility of organic materials makes them particularly attractive for rollable or flexible displays. One of the limitations of organic semiconductor materials, compared to silicon technology, is their intrinsically lower mobility. Exploiting interfacial phenomena to improve molecular ordering of the semiconductor layer during device processing. We will expand on the latter approach, where the interfaces are engineered to enhance device performance.
One of the areas of interest lies in the integration of a plasma-enhanced chemical vapor deposited (PECVD) gate dielectric with a solution-processable organic semiconductor for OTFT fabrication. Since a major driving force behind OTFT technology is the manufacture of low-end, low cost, and disposable electronic devices, this demands a fabrication process that allows high volume production at low cost.
Conventional photolithography processes for manufacturing silicon-based microelectronics are not completely amenable to organic electronics. As the material properties and processing technology for organic electronics continue to advance and mature, the next phase of development is directed at integrating OTFTs into circuits and systems. Finally, the scientific and technical knowledge acquired from these investigations is applied to demonstrate the integration of OTFTs into functional circuits for active-matrix display and RFID applications (Chapter 7.1). The results presented here stem primarily from research conducted at the Giga-to-Nano (G2N) Labs, University of Waterloo, in collaboration with the Xerox Research Centre of Canada (XRCC), which granted access to its high quality, high performance, stable organic semiconductor material.
With the aim of improving OTFT performance, optimization of PECVD gate dielectrics is explored in Chapter 4.1. Flexible and transparent electronics have been studied intensively during the last few decades.
The contact resistances between the metal (drain and source) electrodes and the semiconductor reduce the maximum current that will flow through the device in the on-state. In the MOSFET technology, the creation of a nanoline acting as the gate electrode is sufficient as the source and drain contact areas are defined subsequent to the ion implantation. Output characteristics of an inverted coplanar pentacene OTFT using SiO2 as gate dielectric (L = 1 ?m, W = 1000 ?m). As the thermal growth of SiO2 cannot occur on other substrate materials with individual gate contacts, other deposition techniques for the gate dielectric are required for the realization of digital circuits. Output characteristics of an inverted coplanar pentacene OTFT using a high-k dielectric (L = 10 ?m, W = 1000 ?m and tins = 200 nm). Figure 8 shows the electrical characteristics of the device during the long-term experiment. VDS—IDS characteristics of an inverted coplanar pentacene OTFT at VGS = ?40 V using SiO2 as gate dielectric after 0, 3, 6 and 9 months (L = 1 µm, W = 1000 µm and tox = 110 nm). Behavior of the electrical parameter of an inverted coplanar pentacene OFET-device after 9 months of investigation. Transfer characteristics of an inverted coplanar pentacene OTFT using SiO2 as gate dielectric (L = 1 µm, W = 1000 µm and tox = 110 nm). Starting from the periodic table of the elements and molecular engineering, over a century of research has explored most obvious phenomena of bulk and thin-film materials.
They are currently looking for industrial partners to efficiently scale-up the research by fabricating arrays of thousands of these sensors and testing them in real marine environments.
French partners STMicroelectronics, Soitec, and Leti will also collaborate within the scope of the EU-project Medea. Then, the pseudomorphic SiGe layer is relaxed using a He+ implantation and an annealing step. The objectives of this project are to integrate performance boosters in fully- and partially-depleted SOI for Low Power and High Performance, to validate these technologies by fabricating complex 45nm node demonstrators directly comparable with bulk Si and to develop design kits and SOI-adapted circuit design for evaluation by application designers. Novaled will provide its organic dopants to the Holst Centre for applications as displays and circuits. These effects are also relevant for OTFT devices, as the carrier injection from drain and source into the organic material has a major influence on the device performance.
With the potential for easy and low-cost manufacturing, OFTF could change the way we use electronics today. There are always ups and downs in our world, and we learn to “make hay while the sun shines.” Where has the sun been shining lately? Energy Secretary, is reportedly scrambling to hire experienced staff to help him spend tens of US$ billions in alternative energy stimulus dollars. On completion, Fab 2 is expected to have an annual manufacturing capacity of 500 megawatts per year. The 4200-SCS replaces a variety of electrical test tools with a single integrated characterization solution, and works for applications including semiconductor technology development, process development, and materials and device research labs. The new cables connect any modern semiconductor parameter analyzer to a Cascade Microtech or SUSS MicroTec prober, and allow for switching between measurement types without recabling.
The Keithley Test Environment Interactive (KTEI) V7.2 upgrade includes nine new solar cell test libraries, an expanded frequency range for the system’s C-V measurement capability, and support for the company’s new nine-slot Model 4200-SCS instrument chassis. Lowering the frequency range to 1kHz (from the previous 10kHz) provides for testing of LCDs and organic semiconductors such as organic light-emitting diodes (OLEDs), and also allows for DLCP. To be sure, successively lower capacitances would have nicely lowered the RC delay factor in interconnects, but new materials have been difficult to find and expensive to integrate. We’ve taken a different approach,” said Tim Archer, executive vice president of the PECVD business unit, in an exclusive interview with BetaSights. Still, the ULK material requires a cure step that outgases some material, and data shows the material’s k value reducing along with density.
Designers can transition from dummy fill to density-based fill, or to full model-based fill, depending on the demands of their designs and target manufacturing process. Metal “fill” attempts to achieve an even distribution across the die by adding non-functional metal shapes to “white space” regions in a design. Achieving even greater accuracy requires detailed simulation of the CMP process, and so Calibre now provides its own CMP simulator with models for leading fabs validated against silicon. More about DFM and CMP, from exclusive interviews with Buehler-Garcia and CMP guru Michael Fury will be in the next BetaSights Newsletter.
For the last 12 years, CVD SiOC has been the dominant low-k dielectric, as predicted by the cost model.
During an expert panel discussion on CMP integration with low-k materials (moderated by this editor, summarized in “Chemical-Mechanical Planarization (CMP) technology consensus 09Q1” publication available at the site), Dick James, of reverse-engineering expert firm ChipWorks, disclosed that he had recently seen the first use of a PLK in a commercial chip his company had examined. In particular, for CMP most workable integrations use a capping layer of another dielectric such as standard CVD SiOC or a spin-on undoped silicate glass (USG). MPS thin films are formed from ring-type siloxanes (with high carbon content) in CVD chambers, resulting in dielectric k=2.5 and resistance to plasma-induced damage. NEC experimented with He plasma treatment to alter the MPS surface, and found that 15 seconds reduces carbon to make the surface hydrophillic, but treatment for >30 seconds tends to form a top crust which cracks and shows as scratches. I’d intended the original title to be somewhat playful; since TSV is chip-level while TMV and PoP are of course inherently package-level technologies, the title called into question when TSV might be used in place of PoP. The electronic tag is the first in the world to succeed in temperature sensing and transmitting temperature data on commercial frequency.
A wide range of application is expected in manufacturing process management and healthcare market since the plastic electronic tag is light, thin, and bendable. The research and development is very active for applications such as next generation semiconductor and electronic element. The group also successfully developed an electronic tag that can sense temperature and transmit temperature data at the commercial frequency.
Based on this, an organic sensor with high sensitivity in room temperature that can be coated at low temperature was developed.
Within Tokyo University a consortium of companies called "High-end Organic Semiconductor Development and Training Center" was organized to conduct development spanning from organic material, panel material, and device. He is also the CTO of Ignis Innovation Inc., Waterloo, Canada, a company he founded to commercialize technology on thin film silicon backplanes on rigid and flexible substrates for large area electronics.
Nevertheless, authors, editors, and publisher do not warrant the information contained in these books, including this book, to be free of errors.
No part of this book may be reproduced in any form a€“ by photoprinting, microfilm, or any other means a€“ nor transmitted or translated into a machine language without written permission from the publishers.
Their technological edge lies not only in their ease of processability but in their ability to flex mechanically.


A major driving force behind this technology lies in the ability to manufacture low-end, and disposable electronic devices. We acknowledge the contributions of several colleagues in these laboratories whose expertise ranged from materials processing and TFT integration to circuit and system design. The scope of this book is to advance OTFT integration from an engineering perspective, and not material development, which is the strength of chemical physicists. An alkyl group is a functional group or side-chain that, like an alkane, consists solely of singly-bonded carbon and hydrogen atoms.
In this excited state, there is a partial transfer of elementary charge from the donor to the acceptor.
The conductivity of these materials can be tuned by chemical manipulation of the polymer backbone, by the nature of the dopant, by the degree of doping, and by blending with other polymers.
This system results in a general delocalization of the electrons across all of the adjacent parallel aligned p-orbitals of the atoms, which increases stability and thereby lowers the overall energy of the molecule. Although a€?dielectrica€? and a€?insulatora€? are generally considered synonymous, the term a€?dielectrica€? is more often used when considering the effect of alternating electric fields on the substance while a€?insulatora€? is more often used when the material is being used to withstand a high electric field.
It is an object intended to support or separate electrical conductors without passing current through itself. Carrier mobility is a quantity relating the drift velocity of electrons or holes to the applied electric field across a material; this is a material property.
It is called a€?organica€? electronics because the polymers and small molecules are carbon-based, like the molecules of living things.
A number of commercial opportunities have been identified for OTFTs, including flat panel active-matrix liquid crystal displays (LCDs) or active matrix organic light-emitting diode displays (AMOLEDs), electronic paper (e-paper), low-end data storage such as smart cards, radio-frequency identification (RFID) and tracking devices, low-cost disposable electronic products, and sensor arrays; more applications continue to evolve as the technology matures [4].
Fabrication of organic electronics can be done using relatively simple processes such as evaporation, spin-coating, and printing, which do not require high-end clean room laboratories. The advancement in organic semiconductor materials is starting to prompt the transition of the technology from an academic research environment to industrial research and development (R&D).
To achieve these cost targets, low-cost materials, cost-effective processes, and high-volume manufacturing infrastructure are required. It must be noted that organic semiconductor devices do not offer the same electrical performance as silicon devices. Specifically, printed organic semiconductor materials are strong candidates for novel electrically active display media. Polymer Vision, a spin off from Royal Philips Electronics, was a pioneer in demonstrating the capability of rollable displays, which were produced by combining ultrathin flexible OTFT-driven active-matrix backplane technology and flexible electronic ink (E-Ink) display technology. The RFID tag is a wireless form of automated identification technology that allows non-contact reading of data, making it effective for manufacturing, inventory, and transport environments where bar code labels are inadequate. Personal electronic devices incorporating small displays based on organic light-emitting diodes (OLEDs) are now available. Most organic semiconductor thin films are composed of a mixture of polycrystalline and amorphous phases.
Examples of interfacial phenomena include semiconductor alignment using self-assembled monolayers (SAMs), surface-mediated molecular ordering, surface dipoles, physical alignment, and photoalignment [35]. Moreover, the process should be able to produce stand-alone devices, device arrays, and integrated circuits (ICs) of acceptable operating speed, functionality, reliability, and lifetime. Although photolithography has the advantage of producing high resolution, complex device structures with excellent precision, the process must be modified to ensure compatibility with organic materials. It is not within the scope of this book to review organic semiconductor material development (which is the strength of chemical physicists), but rather to advance OTFT research from an engineering and integration perspective.
In particular, Xerox's solution-processable poly(3,3a€?a€?a€?-dialkylquarterthiophene) (PQT-12) polymer semiconductor forms the basis for the majority of the OTFT experimental work [10] discussed in this book. We begin with an introduction to organic electronics and market opportunities for OTFT technologies in Chapter 1.1. Finally, Chapter 8.1 presents a summary of the outlook and future challenges related to OTFT integration. National Institute of Standards and Technology (NIST) (2000) Project Brief: Printed Organic Transistors on Plastic for Electronic Displays and Circuits.
PolyApply (2004) The application of polymer electronics towards ambient intelligence (POLYAPPLY), Framework Programme 6 (FP6), European Commission. NAIMO Project (2004) Nanoscale Integrated processing of self-organizing Multifunctional Organic Materials (NAIMO), Framework Programme 6 (FP6), European Commission. OSAD(2007) Organic Semiconductor Analyst (OSA) Directa€“a Weekly Newsletter on the Organic Semiconductor Industry, Monday, 22 October 2007, B.5 (39). The technique establishes the possibility of fabricating innovative products, from flexible displays to radio-frequency identification tags. IntroductionNowadays, transparent and flexible electronics are one of the technologies with the widest range for innovative products, so they are the focus of several research groups and enterprises. Nevertheless, as a Schottky barrier is formed at those contacts, the contact resistance during the transistor off-state should be high enough to prevent a high leakage current.
In contrast, to integrate nanoscaled TFTs on glass and flexible substrates an additional step is required to define the channel length of the transistor by a nanogap.
Organic Based TFTThe properties of the gate dielectric are essential for the performance of OFET-devices.
Measurement under vacuum conditions (black curves) and after the impact of oxygen (red curves).
The researchers knew that the fishy hairs were sensitive, so measuring the hairs with optical and confocal fluorescence microscopy allowed them to set initial size, aspect-ratio, and surface complexity parameters for experiment.
Novaled currently develops dopant and host materials which can be processed both in vacuum and in solution.
The challenge has been in finding the right combination of specialty materials that can be printed across large areas. Photovoltaic (PV) and MEMS industries have continued to grow lately, as have the fortunes of companies suppplying technologies to these lines.
The twin goals are to stimulate the economy in general, and to develop new technologies that could lead to energy independence.
Solyndra estimates that the construction of this complex will employ 3,000 people, the operation of the facility will create over 1,000 jobs, and hundreds of additional jobs will be created for the installation of Solyndra PV systems, in the U.S. Though Global Foundries’ major fab is in Dresden, Germany, and major funding is in Abu Dhabi, the spin-out’s headquarters is in Sunnyvale, California so that’s where the new staff will likely sit. The test systems’s modular architecture allows for easy field upgrades, like those just released. In addition, test setup changes can be made while the probe needles are in contact with a wafer, reducing pad damage and maintaining the same contact impedance for all three types of measurements. With complex interdependent trade-offs in interconnect materials today, there are inherent complexities in the solutions as well as in the descriptions of those solutions. In particular, dielectric barrier and etch-stop layers require relatively higher k value such that the effective k for the whole dielectric stack (see figure) is always greater than that for the main low-k film alone. The company officially has no comment on comparisons between its ULK and the molecular pore stack (MPS) ULK shown by NEC (Ref: BetaBlog 090317). The new capability comes from combining the company’s Calibre litho modeling with the CMP sensitivity modeling acquired with Ponte Solutions last year.
Because the rapidly changing CMP process often requires model updates, it allows users to create and calibrate their own thickness models, a capability that is unique in the industry. However, as with any flexible modeling tool it is utterly essential to have proper inputs, so take the training if you license a seat. More about CoO, as well as the right way to estimate real fab costs for different tools, will be covered in the next BetaSights Newsletter.
Fujitsu is now fabbing Via Technologies’ new Nano CPU for “surfbored” (joke spelling intentional) notebooks, using nano-clustering silica (NCS) PLK of k~2.3.
The Via Nano chip fabbed by Fujitsu shows NCS capped with a layer of CVD SiOC according to ChipWorks (see figure).
With small average pore size (<1 nm) there is low potential for water-absorption with MPS films, and having smaller pores reduces intrinsic line edge roughness (LER). Using a He-plasma treatment in the 15-20 seconds range is thus key to cost-effective integration of MPS in dual-damascene Cu flows.
Thus, while edge-connection technology exists, it must win competiton with wire-bond, flip-chip, and now TSV, and that may be difficult. The semiconductor digital circuit is designed for low power consumption and can be manufactured in an ambient temperature and environment. Moreover, the sensor function can also be produced by coating method which proved that it can be used as a logistic management tag with temperature sensing feature. The consortium aims to develop not only RFID tag but also a wide range of high mobility organic electronic devices. The development is conducted under NEDOa€™s strategic low energy technology innovation program called a€?Development of Plastic Electronic Tag using Innovative High Performing Organic Transistora€?. He has held Visiting Professor appointments at the Physical Electronics Laboratory, ETH ZA?rich and at the Engineering Department, University of Cambridge, UK. After two years of postdoctoral studies at Queen's University, Kingston, Canada, he joined the Xerox Research Centre of Canada in 2001 as a research scientist working on organic transistor materials design and process. Prior to his relocation to Singapore in 2007, Professor Ong was a Senior Fellow of the Xerox Corporation, and a manager of Advanced Materials and Printed Electronics at the Xerox Research Centre of Canada.
Readers are advised to keep in mind that statements, data, illustrations, procedural details or other items may inadvertently be inaccurate. This makes them highly favorable for implementation on robust substrates with non-conventional form factor. By assimilating existing materials, techniques and resources, the book explores a number of approaches to deliver higher performance devices and demonstrate the feasibility of organic circuits for practical applications. A CT complex composed of the tetrathiafulvalene (TTF, a donor) and tetracyanoquinodimethane (TCNQ, an acceptor) was discovered in 1973. Dielectric encompasses the broad expanse of nonmetals (including gases, liquids, and solids) considered from the standpoint of their interaction with electric, magnetic, of electromagnetic fields. Field-effect mobility or effective mobility describes the mobility of carriers under the influence of the device structure in field-effect transistors. This is as opposed to traditional electronics which relies on inorganic conductors such as copper or silicon. There are two major classes of organic semiconductors, which overlap significantly: organic charge-transfer complexes, and various a€?linear backbonea€? polymers derived from polyacetylene.
Thus, organic semiconductors have appeal for a broad range of devices including transistors, diodes, sensors, solar cells, and light-emitting devices. For example, solution-processable organic thin films can be deposited by spin coating, enabling fast and inexpensive coverage over large areas.
Photoconductive organic materials were discovered in the 1970s and were used in xerographic sensors.
The shift toward industrial R&D is aided by the establishment of several government-sponsored research initiatives [15, 16], the founding of various organic electronics driven associations and companies [17a€“19], and the development of IEEE standards for the testing of organic electronics devices [20]. The development of high-volume roll-to-roll manufacturing platforms for fabrication of organic circuits on continuous, flexible, low-cost substrates, has been reported. While silicon technology is aimed for high-end, high performance, and high processing power electronic products, organic semiconductor technology appeals for lower-end, cost-effective disposable electronics products.
In January 2008, Polymer Vision introduced their first rollable display product, called ReadiusA®, a pocket-sized device, combining a 5a€? rollable display with high speed connectivity. However, many challenges still remain that are currently hindering the wide adoption of OTFTs in electronic devices. The hopping process between molecules in the disordered regions often limits charge-carrier mobilities in organic semiconductor films [34]. Surface control using SAMs is a well-known technique for such interface modifications and can provide microscopically good interface regulations.
The two interfaces dictate charge transport and charge injection in OTFTs, respectively, thus having an overriding influence on the device characteristics. Past experiments have reported limited OTFT performance with a PECVD SiNx gate dielectric, and have attributed this to surface roughness and unfriendly (or non-organic-friendly) interfaces of SiNx. However, an integration process that can meet the above requirements for production of high yield, stable OTFTs is, currently, non-existent. By utilizing and assimilating existing materials, techniques and resources, we explore a number of approaches to deliver higher performance devices and demonstrate the feasibility of organic circuits for practical applications.
Chapter 2.1 examines the OTFT technology in greater depth, with a review of fundamental properties of organic semiconductors and a discussion of OTFT operation, device architectures, and material selection.
The objectives for these investigations are to enhance OTFT characteristics via functionalization of the gate dielectric material and the device interfaces, and to develop a better understanding of the materials and interfaces for OTFTs.
The structural design of the book is summarized in , which illustrates the flow of the various topics related to advancing device manufacture, device performance, and OTFT circuit integration. IEEE Standard for Test Methods for the Characterization of Organic Transistors and Materials.
Typically, large-area polymeric substrates such as polypropylene (PP) or polyethylene terephthalate (PET) are used, which produces new requirements for the integration processes. One reason for this interest is the chance to integrate identification tags, smart cards or flexible displays using almost the same integration processes. The arrangement of these elements has a strong influence on both the device performance and the integration process itself. For staggered structures, a major contribution to the contact resistance is related to access resistance. Figure 5 shows the adaptation of the SWEB technique to avail the process to flexible substrates. Roughness and polarity of the insulating layer surface are crucial for the morphology and distribution of the electronic states of the grown organic semiconductor.
Triethylsilane forms silicon dioxide by the separation of ethyl groups from the residual silane under low pressure and continuous oxygen flow.
The vast complexity of natural micro- and nano-scale structures that are indirectly templated by DNA in living organisms. The synthetic hairs are formed from a core of standard SU8 photo-epoxy used in MEMS and packaging fabs, then coated with a “cupula” of a UV-cross-linked hydrogel (see figure). The strain generated depends on the layer thickness and the degree of relaxation of the SiGe layer. On March 20th, Solyndra announced that it is the first company to receive an offer for a U.S. The cables are designed for compatibility with the 4200-SCS, as well as with other test instruments.
To discuss such complexities, instead of a one-time press release the company has launched a new technology information page on online. We think that we can deliver a full stack that will rival or beat the k-effective of the PLK.” The barrier layer depositions and UV cure steps really can make or break k-effective. More exclusive info on low-k dielectric integration and Novellus’ plans will be in the next BetaSights Newsletter. We need fill in the right places to optimize performance while minimizing manufacturing variations. The company claims that there is margin for overpressure in CMP using this dielectric without a cap. Professor Ong currently has a patent portfolio of 187 US patents and about 100 refereed papers on enabling materials, processes, and integration technologies. Since its proof of concept in the early 1980s, progress in organic electronics has been impressive with performance attributes that are competitive with the inorganic counterparts. The process should be able to produce stand-alone devices, device arrays, and integrated circuits of acceptable operating speed, functionality, reliability, and lifetime. Field-effect mobility is device-specific, not material-specific, and includes effects such as contact resistances, surface effects, and so on.
This book focuses on the investigation of polymer organic semiconductors; thus, in most cases, the term a€?organic semiconductora€? and a€?polymer semiconductora€? are used interchangeably. The announcement of conductive polymers in the late 1970s [6], and of conjugated semiconductors and photoemission polymers in the 1980s [7], gave new impulse to the activity in the field of organic electronics. The increased cooperative efforts between academia, industry, and government are vital to the development of a strong materials and manufacturing infrastructure [21a€“26]. These platforms are based on the integration of lithography, vacuum deposition, and printing technologies. An overview of these OTFT-based applications and their current market status is presented next.
The active-matrix display backplane was inkjet printed and drove a 3000-pixel display that was fabricated on glass.
The ReadiusA® demonstrated a merger of the reading-friendly strengths of electronic-readers with the high mobility features of mobile phones, along with instant access to personalized news and information [31]. We will investigate interface modification techniques for these two device interfaces, with an attempt to enhance device performance.
Inkjet printing technology is particularly attractive because it offers the advantages of fast, direct imaging and single-step print processing, precise deposition of the organic ink only where it is needed (thus reducing waste), compatibility with flexible substrates, large area processing, and high material usage efficiency. Poster presented at the Society for Information Display International Symposium Exhibition, and Seminar, Baltimore.
2010 IEEE International Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 7-11 February 2010, pp. A key element for flexible and transparent electronics is the thin-film transistor (TFT), as it is responsible for the driving current in memory cells, digital circuits or organic light-emitting devices (OLEDs). Moreover, the cost of these devices is kept low due to the innovative use of newly created or adapted processes for large-area and flexible substrates.


First, the position of the structure is defined by conventional photolithography, where the sacrificial layer is the photoresist itself (Figure 5a). The first OFET-devices were developed using silicon dioxide, a standard dielectric material in MOSFET technology. From gecko toes to lotus leafs, bio-inspired researchers have found that studying what nature has evolved points the way to fabricating new functional materials.
Department of Energy (DOE) loan guarantee under Title XVII of the Energy Policy Act of 2005.
Because the percentage of total thickness variability per layer has increased at each node (see figure), CMP variations are much more significant below 65nm, and traditional dummy fill approaches are no longer adequate. Wu is a Principal Scientist at the centre, leading Xerox's Printable Electronic Materials project. Many of the technology programs he managed at Xerox have won awards including the Nano-50 Award for Materials Innovation (2007) and for Nanotechnology Commercialization (2007), the ACS Innovation Award (2006), the Connecticut Quality Improvement Gold Award (2006), and the Wall Street Journal Technology Innovation Runner-up Award (2005). In particular, organic electronics is attractive from the standpoint of complementing conventional silicon technology, thriving in a different market domain that targets lower resolution, cost-effective mass production items such as identification tags, smart cards, smart labels, and pixel drivers for display and sensor technology.
However, this comes with its fair share of challenges, which we have attempted to address in this book. Sazonov (University of Waterloo), Dr Yuri Vygranenko (Instituto Superior de Engenharia de Lisboa), Dr D. The text begins with an assessment of organic electronics and market opportunities for OTFT technology. In addition, low-temperature processing and the mechanical flexibility of organic materials make them highly favorable for implementation on robust substrates with non-conventional form factors.
Polyacetylene was one of the first polymers reported to be capable of conducting electricity [8], and it was discovered that oxidative doping with iodine causes the conductivity to increase by 12 orders of magnitude [9]. It has been forecast that an organic semiconductor fabrication facility can be built for far less than the cost of a silicon semiconductor fabrication facility [3]. Note that, at present, a-Si thin film transistors (TFTs) and polycrystalline silicon (poly-Si) TFTs are the key backplane technologies used in flat panel display products.
In early 2007, the world's first factory was built to produce plastic electronic devices [18]. Demand for larger mobile displays is accelerating as telecom players push mobile content and mobile advertisements. For example, a 64-bit inductively-coupled passive RFID tag on a plastic substrate was demonstrated, operating at 13.56 MHz and with a read distance of over 10 cm. These technical challenges can be grouped into two categories: device performance and device manufacture. It is scalable to large areas and can be deposited at low temperatures, making it compatible with plastic substrates.
However, because the requirements of printing electronic functions are very different from those of printing visual images, the adaptation of inkjet systems for processing organic electronic devices will require extensive optimization of printing parameters and processing conditions; in addition, technological concerns such as layer continuity and multilayer registration must be resolved.
In the case of coplanar setups, the drain and source electrodes are already in contact with the formed accumulation layer, which results in a low access resistance. A PECVD-SiO2 layer is deposited at low temperature and etched anisotropically (Figure 5b,c). The growth process of SiO2 can be well-controlled, providing a low defect density and a smooth surface to produce well-oriented organic semiconducting films [44,45,46]. To avoid the oxidation of the gate metal during the LTO-deposition, an additional step to nitrify the titanium can be performed.
Therefore, a chip carrying a proceeded OTFT template was bonded and connected to the measurement setup, followed by placement in a vacuum chamber. Georgia Tech researchers used DARPA money to copy and improve on the flow-sensing hairs of the blind cave fish, and talked about it at the American Physical Society meeting on March 20. The latter is further described in Chapter 2.1, examining device architectures and material selection. In general, organic electronic devices are not expected to compete with silicon devices in high-end products, because of their lower speed as compared to silicon.
This discovery and the development of highly-conductive organic polymers was credited to Alan J. The high cost of silicon-based foundries can be attributed to the sophisticated wafer processing and handling equipment, high-resolution lithography tools, wafer testing equipment, clean-room environment, and costly chemical distribution and disposal facilities.
Therefore, OTFTs are not intended to displace a-Si TFTs in large-area high-resolution flat panel displays. The solution is to unroll the display when needed and simply store it away when not in use. These specifications are approaching item-level tagging requirements, paving the way for low-cost high-volume production of RFID tags, with the potential to replace barcodes [19, 32, 33]. We believe the critical factors to enable integration of SiNx in organic electronics lie in identifying a suitable SiNx composition and an agreeable interface modification process.
Inkjet printed organic devices with good performance have been demonstrated; however, low device yield is an issue.
Additionally, we present a comparison between the use of the semiconducting organic small-molecule pentacene and inorganic nanoparticle semiconductors in order to integrate TFTs suitable for flexible electronics.
They are responsible for the driving current in memory cells, digital circuits or for light-emitting diodes (LEDs).
Besides the high electrical stability, thermally grown SiO2 on a heavily doped Si wafer acts as template to evaluate new synthesized organic semiconducting materials.
Nevertheless, large leakage currents and a low on-off ratio that are related to carbon atoms from ethyl groups prevent the building of digital circuits.
Treasury’s Federal Financing Bank to expand its solar panel manufacturing capacity in California. Her research interests are in the field of nano- and thin-film technology for applications in large area and flexible electronics, including displays, sensors, photovoltaics, circuits and systems. Steacie Fellowship, and was awarded the Canada Research Chair in nano-scale flexible circuits. In contrast, the cost reduction forecast for an organic electronic manufacturing facility is expected to be derived from lower materials cost, less sophisticated equipment, simpler manufacturing technologies, less stringent demands on clean-room settings, and reduced waste output. Instead, they will have a bigger impact on lower-cost flexible displays and e-paper applications.
Therefore, rollable display enabled devices are expected to be an emerging commodity for new generations of portable communication devices, thus presenting exciting commercial opportunities for OTFT-driven display backplane technology. Strategies to address these factors and to enable the use of SiNx while delivering acceptable device performance remain the ultimate goal. We will address the challenges in OTFT manufacture by exploring a hybrid manufacturing approach that combines a photolithography process with a novel inkjet printing technique. Moreover, a technique for integration with a submicron resolution suitable for glass and foil substrates is presented. Another characteristic of this technology is the opportunity to introduce new materials, which improve the electrical performance, simplify the integration process or even add new mechanical properties to the final product.Organic and inorganic semiconductors have been used to integrate TFTs for more than 20 years [1,2]. The position of the gate electrode is also used to classify the setups as either bottom-gate (Figure 2a,b) or top-gate devices (Figure 2c,d).
In order to achieve a nanogap from a nanoline, a metal is evaporated anisotropically (Figure 5e). As a first investigation, 30 nm pentacene were evaporated under high-vacuum conditions as an active semiconducting layer, in which the drain and source contacts consist of gold. Even after an additional thermal treatment, just a slightly better breakdown voltage can be observed [47].By using PECVD-deposition techniques, a further decrease of the process temperature can be achieved.
Subsequent to the measurement under high-vacuum conditions, the chamber was flooded with pure technical oxygen before repeating the measurement. It is expected to thrive in a different market domain targeting lower resolution, cost-effective mass production items such as identification tags, smart cards, and pixel drivers for display and sensor technology. MacDiarmid, and Hideki Shirakawa, who were jointly awarded the Nobel Prize in Chemistry in 2000 for their 1977 discovery and development of oxidized, iodine-doped polyacetylene.
However, the potential savings in the manufacturing cost of organic electronics come with the trade-off of lower performance. This delivers an integration strategy with workable manufacturing yields while lowering costs compared to conventional processes. They exhibit better characteristics in comparison to amorphous silicon-based transistors due to the achieved performance and low production cost.
The inverted coplanar layout permits the semiconducting layer to be deposited in the last step. By using a selective etching process, the PECVD-SiO2 is removed creating a nanogap (transistor channel) as shown in Figure 5f.
The transistor exhibits a threshold voltage of about 1.5 V and an on-off ratio of 103 at a drain-source voltage of VDS = ?40 V [47]. At typical process temperatures between 130 °C and 300 °C, silicon dioxide is formed by a chemical reaction of silane and oxygen. Li has co-authored a book entitled CCD Image Sensors in Deep-Ultraviolet (2005), and has published articles in various scientific journals. He is the co-author of two books, Microtransducer CAD and CCD Image Sensors in Deep-Ultraviolet, and serves on technical committees and editorial boards in various capacities.
Chapter 7.1 presents examples of functional circuits for active-matrix display and other applications. Nevertheless, when pursuing a cost-efficient production with a high reliability and restrained mechanical characteristics, there are new requirements.
For this reason, the semiconducting film will not suffer from chemical impacts and other integration process steps. Due to the low temperatures, the nitridation of the titanium gate electrode is not necessary, but a high defect density and low electrical stability restrain the exclusive use of PECVD-oxide for OTFT [49]. For other layouts, the semiconductor has to withstand different processes, as for example lithography, etching or annealing steps.Deposition methods for metals, dielectrics, semiconductors and all materials used in the integration process should be also entirely suitable for flexible electronics. Nevertheless, when the technique is performed over the gate dielectric, the anisotropic etching of the PECVD-SiO2 can damage the dielectric layer, if the etching time is not defined carefully.
In order to improve the growth process of the pentacene film, an oxygen plasma surface treatment of the dielectric material was performed before the evaporation. Nevertheless, PECVD-oxide can be used as an oxidation barrier for the metal gate electrode, replacing the time-consuming step of nitrifying titanium.
For instance, the use of non-malleable metal connections or dielectrics may induce a failure after bending the substrate. However, there are variations, either in the quality of the material, temperature or production costs. Furthermore, all processes should be selected to fulfill the substrate requirements; for instance, the process temperature is limited to 150 °C.
Figure 6 shows the electrical characteristics of OFET-devices using thermally grown SiO2 as insulating layer (a) without and (b) with prior treatment by an oxygen plasma. Admittedly, a reduction of the leakage current can be observed compared to the above mentioned LTO-process, but a rather low on-off ratio exhibits the impossibility of building digital circuits [47].Flexible electronic devices using polymeric substrates such as polyethylene terephthalate (PET) or polypropylene (PP) are sensitive to thermal treatments.
For this sake, all components (materials and integration processes) have to be selected carefully to fulfill these requirements.In this review paper, we concisely address the fundamental concept, electrical analysis and limitations of the flexible electronic technology.
For the deposition of the semiconductor, commonly vacuum techniques produce a denser film with higher charge carrier mobilities [6,7].During the last few decades, pentacene seems to be the most promising candidate for organic semiconductor applications. Evidently, the surface treatment leads to a threshold voltage shift to 17.2 V [47] regarding the polarization of the dielectric due to the generation of free bonds at its surface [48]. High process temperatures, electrical instability and the low dielectric constant of SiO2 (k = 3.9) create a demand for other deposition techniques and materials.
Additionally, we present a comparison between organic and inorganic based TFTs, as well as an integration routine in order to fabricate submicron structures on foil at reduced costs. Typically, pentacene layers are deposited by evaporation under high- or ultra-high-vacuum conditions [8], whereby the substrate temperature can be vary between room temperature and 80 °C to improve the self-ordering of the semiconductor molecules [9,10,11]. Furthermore, the electrical strength diminished, resulting in an increasing leakage current at off-state. Reactive sputtering techniques provide process temperatures down to room temperature, but it should be mentioned that sputtering of the gate dielectric leads to a high surface roughness.
Nevertheless, the surface treatment leads to higher drain currents at lower gate voltages, regarding the increased pentacene crystallites at the dielectric surface.
Furthermore, deposition under low vacuum conditions assisted by an inert gas stream is possible [8].Nowadays, new materials promising good environmental stability and higher mobilities have been synthesized.
AFM studies found a crystallite diameter of 250 nm at untreated and 1 ?m at treated SiO2 surfaces, respectively [47].
Furthermore, it is shown that the stoichiometric ratio of oxygen and tantalum is important to control. Various research groups focus on materials such as dinaphtho(2,3-b:2?,3?-f)thieno(3,2-b)thiophene (Cn-DNTT) and 2,7-dioctyl(1)benzothieno(3,2-b)(1)benzothiophene (C8-BTBT), which can be deposit by thermal evaporation or from solutions, respectively [13,14,15,16].
An excessive amount of tantalum leads to a metallic character in the insulating layer [50,51].Inorganic dielectric materials have in common that they lack mechanical elasticity, hence they are partly usable in flexible electronic devices. However, polymeric dielectrics are featured with high mechanical flexibility and rather low processing temperatures. With this technique it is possible to deposit binary compounds such as ZnO, In2O3, and semiconductor compositions with different ratio between elements, such as IZO, IGO, ZTO, GIZO [19,20,21]. A commercially available coating varnish, Bectron, which is based on modified alkyd chemistry, was used for initial investigations.
Its low curing temperatures of 80 °C and deposition by spin-coating show possible application for flexible electronics.
Limited stability against solvents that are part of optical lithography and insufficient control of the deposited layer thickness led to efforts being discontinued [47].Organic-inorganic nanocomposites are intertwining the advantages of inorganic and polymeric dielectrics.
While the polymeric matrix leads to the flexible attributes of the nanocomposite material, the permittivity can be adjusted by the involved inorganic component.
Therefore, a high-k-resist based on hydrolyzed and partially condensed ethyl silicates was used. The high-k-resist contains different amounts of zirconium dioxide or titanium dioxide resulting in dielectric constants between 9 and 12 [47]. The transistor performance can be further improved by using a GIZO target [24] or co-sputtering techniques [25]. Additionally, adjusting the pressure in the chamber and the power during the process, the defect concentration as well as the film density can be controlled [26,27]. The curing process consists of a soft-bake step at temperatures of 80 °C, followed by an UV-curing step for cross-linking of the polymeric matrix material.
When oxygen is added, a reactive process occurs and the amount of oxygen in the film can be adjusted [28,29].
The resulting layers exhibit a thickness in the range of 200 nm and 400 nm and a sufficient stability against the common solvents used in optical lithography.Figure 7 shows the electrical characteristics of an OFET-device using a 200 nm thick high-k-resist layer as dielectric material. Atomic layer deposition (ALD) is another method to achieve high-density layers as demonstrated by [30,31].
Nevertheless, these films are deposited under vacuum conditions, increasing the production cost. As active semiconducting material, 30 nm of pentacene was thermally evaporated under high-vacuum conditions. Conjointly, when large area substrates are used, the equipment size will limit the template size.For this reason, methods using solutions have greater potential to fulfill the requirements imposed for large-area and flexible substrates. As organic semiconductors act as active layers in OTFT, the device’s performance is directly affected. For molecular precursors, the temperature in which the semiconductor film will be synthesized depends on the type of precursor [32].
Water vapor and oxygen lead to modifications in the charge carrier field-effect mobility and in the threshold voltage [52,53,54].
Commonly nitrate precursors require lower annealing temperatures than acetate or chloride precursors, and greater performance is achieved [33]. To investigate the impact of ambient humidity and oxygen, long-term experiments were executed. In the case of nanoparticle suspensions, the semiconductor is already synthesized in the form of nanoparticles being dispersed in a solution, either water or other solvents, like ethanol, isopropanol and buthyl acetate. Therefore, an OFET-device using 110 nm of thermally grown SiO2, as insulating layer, on a heavily doped Si substrate was prepared.
That means it is possible to fabricate high-quality nanoparticles in mass production, using high temperature and vacuum processes.
It maintains an attractive cost base and has almost no influence on the transistor integration process. The long-term experiments were performed over a period of 9 months at intervals of 3 months. After the nanoparticle deposition, an annealing process removes the solvent [34,35,36].One of the main advantages of using a solution based process is the variety in coating methods. Most of the literature refers to spin-coating methods; however, methods like inkjet printing, spray coating, doctor blade and Meyer rods have attracted the interest of research groups, due to the opportunity to integrate low-cost devices on large area and flexible substrates either using organic or inorganic semiconductors [17,37,38,39,40].



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