Short Channel Organic Thin Film Transistors

This work takes advantage of high-resolution silicon stencil masks to build air-stable complementary OTFTs using a low-temperature fabrication process. Plastic electronics based on organic thin-film transistors (OTFTs) pave the way for cheap, flexible and large-area products. Over the past few years, OTFTs have undergone remarkable advances in terms of reliability, performance and scale of integration. Many factors contribute to the allure of this technology; the masks exhibit excellent stiffness and stability, thus allowing OTFTs with submicrometer channel lengths and superb device uniformity to be patterned. Furthermore, the OTFTs employ an ultra-thin gate dielectric that provides a sufficiently high capacitance to enable the transistors to operate at voltages as low as 3 V. The critical challenges in this development are the subtle mechanisms that govern the properties of aggressively scaled OTFTs. These mechanisms, dictated by device physics, are well described and implemented into circuit-design tools to ensure adequate simulation accuracy.

Introduction to Thin Film Transistors reviews the operation, application and technology of the main classes of thin film transistor (TFT) of current interest for large area electronics. The TFT materials covered include hydrogenated amorphous silicon (a-Si:H), poly-crystalline silicon (poly-Si), transparent amorphous oxide semiconductors (AOS), and organic semiconductors. The large scale manufacturing of a-Si:H TFTs forms the basis of the active matrix flat panel display industry. Poly-Si TFTs facilitate the integration of electronic circuits into portable active matrix liquid crystal displays, and are increasingly used in active matrix organic light emitting diode (AMOLED) displays for smart phones. The recently developed AOS TFTs are seen as an alternative option to poly-Si and a-Si:H for AMOLED TV and large AMLCD TV applications, respectively. The organic TFTs are regarded as a cost effective route into flexible electronics. As well as treating the highly divergent preparation and properties of these materials, the physics of the devices fabricated from them is also covered, with emphasis on performance features such as carrier mobility limitations, leakage currents and instability mechanisms. The thin film transistors implemented with these materials are the conventional, insulated gate field effect transistors, and a further chapter describes a new thin film transistor structure: the source gated transistor, SGT. The driving force behind much of the development of TFTs has been their application to AMLCDs, and there is a chapter dealing with the operation of these displays, as well as of AMOLED and electrophoretic displays. A discussion of TFT and pixel layout issues is also included. For students and new-comers to the field, introductory chapters deal with basic semiconductor surface physics, and with classical MOSFET operation. These topics are handled analytically, so that the underlying device physics is clearly revealed. These treatments are then used as a reference point, from which the impact of additional band-gap states on TFT behaviour can be readily appreciated. This reference book, covering all the major TFT technologies, will be of interest to a wide range of scientists and engineers in the large area electronics industry. It will also be a broad introduction for research students and other scientists entering the field, as well as providing an accessible and comprehensive overview for undergraduate and postgraduate teaching programmes.

This is a single-source treatment of developments in TFT production from international specialists. It interweaves overlapping areas in multiple disciplines pertinent to transistor fabrication and explores the killer application of amorphous silicon transistors in active matrix liquid crystal displays. It evaluates the preparation of polycrystallin

Dear Readers, Since the ground-breaking, Nobel-prize crowned work of Heeger, MacDiarmid, and Shirakawa on molecularly doped polymers and polymers with an alternating bonding structure at the end of the 1970s, the academic and industrial research on hydrocarbon-based semiconducting materials and devices has made encouraging progress. The strengths of semiconducting polymers are currently mainly unfolding in cheap and easily assembled thin ?lm transistors, light emitting diodes, and organic solar cells. The use of so-called “plastic chips” ranges from lightweight, portable devices over large-area applications to gadgets demanding a degree of mechanical ?exibility, which would overstress conventionaldevices based on inorganic,perfect crystals. The ?eld of organic electronics has evolved quite dynamically during the last few years; thus consumer electronics based on molecular semiconductors has gained suf?cient market attractiveness to be launched by the major manufacturers in the recent past. Nonetheless, the numerous challenges related to organic device physics and the physics of ordered and disordered molecular solids are still the subjects of a cont- uing lively debate. The future of organic microelectronics will unavoidably lead to new devi- physical insights and hence to novel compounds and device architectures of - hanced complexity. Thus, the early evolution of predictive models and precise, computationally effective simulation tools for computer-aided analysis and design of promising device prototypes will be of crucial importance.

Text provides information about advanced OTFT (Organic thin film transistor) structures, their modeling and extraction of performance parameters, materials of individual layers, their molecular structures, basics of pi-conjugated semiconducting materials and their properties, OTFT charge transport phenomena and fabrication techniques. It includes applications of OTFTs such as single and dual gate OTFT based inverter circuits along with bootstrap techniques, SRAM cell designs based on different material and circuit configurations, light emitting diodes (LEDs). Besides this, application of dual gate OTFT in the logic gate, shift register, Flip-Flop, counter circuits will be included as well.

The steady downscaling of device-feature size combined with a rapid increase in circuit complexity as well as the introduction of new device concepts based on non-silicon-material systems poses great challenges for device and circuit designers. One of the major tasks is the development of new and improved device models needed for accurate device and circuit design. Another task is the development of new circuit-simulation tools to handle very large and complex circuits. This book addresses both these issues with up-to-date reviews written by leading experts in the field. The first three chapters of the book discuss advanced device models both for existing technologies and for new, emerging technologies. Among the topics covered are models for MOSFETs, thin-film transitors (TFTs), and compound semiconductor devices, including GaAs HEMTs and HFETs, heterodimensional devices, quantum-tunneling devices, as well as wide-bandgap devices. Chapters 4 and 5 discuss advanced circuit simulators that hold promise for,handling circuits of much higher complexity than what is possible for typical state-of-the-art circuit simulators today.

Electrical Processes in Organic Thin Film Devices A one-stop examination of fundamental electrical behaviour in organic electronic device architectures In Electrical Processes in Organic Thin Film Devices: From Bulk Materials to Nanoscale Architectures, distinguished researcher Michael C. Petty delivers an in-depth treatment of the electrical behaviour of organic electronic devices focused on first principles. The author describes the fundamental electrical behaviour of various device architectures and offers an introduction to the physical processes that play a role in the electrical conductivity of organic materials. Beginning with band theory, the text moves on to address the effects of thin film device architectures and nanostructures. The book discusses the applications to devices currently in the marketplace, like displays, as well as those under development (transistors, solar cells, and memories). Electrical Processes in Organic Thin Film Devices also describes emerging organic thin film architectures and explores the potential for single molecule electronics and biologically inspired devices. Finally, the book also includes: A detailed introduction to electronic and vibrational states in organic solids, including classical band theory, disordered semiconductors, and lattice vibrations Comprehensive explorations of electrical conductivity, including electronic and ionic processes, carrier drift, diffusion, the Boltzmann Transport Equation, excess carriers, recombination, doping, and superconductivity An overview of important electro-active organic materials, like molecular crystals, charge-transfer complexes, conductive polymers, carbon nanotubes, and graphene Practical considerations of defects and nanoscale phenomena, including transport processes in low-dimensional systems, surfaces and interface states In-depth examinations of metal contacts, including ohmic contacts, the Schottky Barrier, and metal/molecule contacts A systematic guide to the operating principles of metal/insulator/semiconductor structures and the field effect A set of problems (with solutions on-line) for each chapter of the book Perfect for electronics developers and researchers in both industry and academia who study and work with molecular and nanoscale electronics, Electrical Processes in Organic Thin Film Devices also deserves a place in the libraries of undergraduate and postgraduate students in courses on molecular electronics, organic electronics, and plastic electronics.

A single-source treatment of developments in TFT production from international specialists. It interweaves overlapping areas in multiple disciplines pertinent to transistor fabrication and explores the killer application of amorphous silicon transistors in active matrix liquid crystal displays.