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Book Electrical Characteristics of Amorphous Indium gallium zinc oxide Thin film Transistors and Enhanced Ultra thin body Mosfets by Charged Buried Oxide

Download or read book Electrical Characteristics of Amorphous Indium gallium zinc oxide Thin film Transistors and Enhanced Ultra thin body Mosfets by Charged Buried Oxide written by 林軒毅 and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Amorphous Indium Gallium Zinc Oxide Thin Film Transistors Non volatile Memory and Circuits for Transparent Electronics

Download or read book Amorphous Indium Gallium Zinc Oxide Thin Film Transistors Non volatile Memory and Circuits for Transparent Electronics written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability to make electronic devices, that are transparent to visible and near infrared wavelength, is a relatively new field of research in the development of the next generation of optoelectronic devices. A new class of inorganic thin-film transistor (TFT) channel material based on amorphous oxide semiconductors, that show high carrier mobility and high visual transparency, is being researched actively. The purpose of this dissertation is to develop amorphous oxide semiconductors by pulsed laser deposition, show their suitability for TFT applications and demonstrate other classes of devices such as non-volatile memory elements and integrated circuits such as ring oscillators and active matrix pixel elements. Indium gallium zinc oxide (IGZO) is discussed extensively in this dissertation. The influence of several deposition parameters is explored and oxygen partial pressure during deposition is found to have a profound effect on the electrical and optical characteristics of the IGZO films. By optimizing the deposition conditions, IGZO TFTs exhibit excellent electrical properties, even without any intentional annealing. This attribute along with the amorphous nature of the material also makes IGZO TFTs compatible with flexible substrates opening up various applications. IGZO TFTs with saturation field effect mobility of 12 â€" 16 cm2 V-1 s-1 and subthreshold voltage swing of 200 mV decade-1 have been fabricated. By varying the oxygen partial pressure during deposition the conductivity of the channel was controlled to give a low off-state current ~ 10 pA and a drain current on/off ratio of 1 x108. Additionally, the effects of the oxygen partial pressure and the thickness of the semiconductor layer, the choice of the gate dielectric material and the device channel length on the electrical characteristics of the TFTs are explored. To evaluate IGZO TFT electrical stability, constant voltage bias stress measurements were carried out. The observed logarithmic depende.

Book Composition Engineering for Solution Processed Gallium Rich Indium Gallium Zinc Oxide Thin Film Transistors

Download or read book Composition Engineering for Solution Processed Gallium Rich Indium Gallium Zinc Oxide Thin Film Transistors written by Isaac Caleb Wang and published by . This book was released on 2018 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal oxides have risen to prominence in recent years as a promising active layer for thin film transistors (TFTs). One of the main reasons for this has been its value in display technology. Conventionally, displays have relied on amorphous hydrogenated silicon (a-Si:H) TFTs but the demand for large area displays with high resolution, fast response time, low power consumption and compatibility with integrated driving circuits have prompted research into other semiconducting materials. As a result, metal oxides have become major prospects to replace a-Si:H with their high-performance electrical characteristics and simplicity of processing, making them valuable switching elements in display technology. Particularly, quaternary metal oxides such as the amorphous Indium-Gallium-Zinc-Oxide (IGZO) have demonstrated extremely high performances as TFTs, prompting extensive research in the field. The conventional method of producing metal oxide thin films has been through vacuum deposition methods such as sputtering. However, for large area applications these vacuum deposition methods face inherent limitations which prevent easy application and device fabrication. Facing these restrictions, solution-processing has become a popularly researched alternative in producing metal oxide thin films due to their simple processing requirements, low cost, and ability to be applied over large areas. In solution-processed IGZO, there have been a couple approaches to improve device performance and stability as well as simplify processing. In this work, we produce a gallium-rich 2:2:1 IGZO TFT using solution processes and study its electrical characteristics and stability. In this paper, we demonstrate a working solution-processed gallium-rich 2:2:1 IGZO TFT and compare it to a solution-processed indium-rich device to quantify its stability and performance. Through this work, we show that solution-processing is a viable fabrication method for gallium-rich IGZO, which can be a high-stability alternative to other compositions of IGZO devices.

Book Amorphous Indium Gallium Zinc Oxide Based Thin Film Transistors and Circuits

Download or read book Amorphous Indium Gallium Zinc Oxide Based Thin Film Transistors and Circuits written by Haojun Luo and published by . This book was released on 2013 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Development of Indium Gallium Zinc Oxide Thin Film Transistors on a Softening Shape Memory Polymer for Implantable Neural Interfaces Devices

Download or read book Development of Indium Gallium Zinc Oxide Thin Film Transistors on a Softening Shape Memory Polymer for Implantable Neural Interfaces Devices written by Ovidio Rodriguez Lopez and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The continuous improvement in electronic active devices has led to several innovations in semiconductor materials, novel deposition methods, and improved microfabrication techniques. In the same way, the implementation of thin-film technology has revolutionized the semiconductor industry. For instance, the field of flexible electronics has utilized novel thin-film electronics components for the fabrication flexible displays, radio frequency identification (RF-ID) tags, and solar cells. Moreover, flexible electronics have sparked a great interest in the field of bioelectronics, for the fabrication of high-spatial-resolution implantable devices for neural interfaces. This incorporation of thin-film technology can potentially enable stimulation and recording the nervous system activity by utilizing novel, minimally invasive, conformal devices. To achieve this, flexible electronics circuits must possess high performance, reliability, and stability, as well as be resilient to mechanical stress and human body conditions, are some of the requirements that flexible electronics must meet for the realization of these devices. Furthermore, the choice of substrates is also critical since it directly affects final properties of the active devices. Substrates, which are mechanically and biologically compliant, are preferred. For this reason, novel, softening materials like thiol-ene polymers are considered in this research. This work centers on the development of Indium-Gallium-Zinc-Oxide (IGZO) thin-film transistors (TFT) using the thiol-ene softening polymer as substrate. Functional IGZO-TFTs were fabricated on top of 50 μm of a thiol-ene/acrylate shape memory polymer (SMP) and electrically characterized. Hafnium oxide (HfO2) deposited at 100°C by atomic layer deposition was used as gate dielectric, and gold (Au) as contacts. The devices were exposed to oxygen, vacuum and forming gas (FG) environments at 250°C to analyze the effects of these atmospheres on the IGZO-TFTs. Improvement in the electrical performance was noticed after the exposure to FG with a significant change in mobility from 0.01 to 30 cm2 V-1s-1, and a reduction in the threshold voltage shift (∆Vth), which it is translated into an increase on stability. Vacuum and oxygen effects were, also analyzed and compared. Furthermore, a time-dependent dielectric breakdown (TDDB) analysis was performed to define the lifetime of the transistors, where a prediction of 10 years at an operational range below 5 V was obtained. Additionally, the TFTs were encapsulated with 5 μm of SMP and exposed to simulated in vivo conditions. Up to 104 bending cycles were performed to the IGZO-TFTs with a bending radius of 5 mm and then, soaked into PBS solution at 37°C for one week to determine the resilience and reliability of the devices. The encapsulated IGZO-TFTs survived to the PBS environment and demonstrated resilience to mechanical deformation with small changes in the electronic properties. The results provided in this research contribute to the development of complex circuitry based on thin-film devices using mechanically adaptive polymers as a flexible substrate and enable the production of multichannel implantable bioelectronics devices.

Book On the Reversible Effects of Bias stress Applied to Amorphous Indium gallium zinc oxide Thin Film Transistors

Download or read book On the Reversible Effects of Bias stress Applied to Amorphous Indium gallium zinc oxide Thin Film Transistors written by Anish Suresh Bharadwaj and published by . This book was released on 2018 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The role of amorphous IGZO (Indium Gallium Zinc Oxide) in Thin Film Transistors (TFT) has found its application in emerging display technologies such as active matrix liquid crystal display (LCD) and active matrix organic light-emitting diode (AMOLED) due to factors such as high mobility 10-20 cm2/(V.s), low subthreshold swing (~120mV/dec), overall material stability and ease of fabrication. However, prolonged application of gate bias on the TFT results in deterioration of I-V characteristics such as sub-threshold distortion and a distinct shift in threshold voltage. Both positive-bias and negative-bias affects have been investigated. In most cases positive-stress was found to have negligible influence on device characteristics, however a stress induced trap state was evident in certain cases. Negative stress demonstrated a pronounced influence by donor like interface traps, with significant transfer characteristics shift that was reversible over a period of time at room temperature. It was also found that the reversible mechanism to pre-stress conditions was accelerated when samples were subjected to cryogenic temperature (77 K). To improve device performance BG devices were subjected to extended anneals and encapsulated with ALD alumina. These devices were found to have excellent resistance to bias stress. Double gate devices that were subjected to extended anneals and alumina capping revealed similar results with better electrostatics compared to BG devices. The cause and effect of bias stress and its reversible mechanisms on IGZO TFTs has been studied and explained with supporting models."--Abstract.

Book Chemical Abstracts

Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2616 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Interpretation and Regulation of Electronic Defects in IGZO TFTs Through Materials Processes

Download or read book Interpretation and Regulation of Electronic Defects in IGZO TFTs Through Materials Processes written by Tarun Mudgal and published by . This book was released on 2017 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The recent rise in the market for consumer electronics has fueled extensive research in the field of display. Thin-Film Transistors (TFTs) are used as active matrix switching devices for flat panel displays such as LCD and OLED. The following investigation involves an amorphous metal-oxide semiconductor that has the potential for improved performance over current technology, while maintaining high manufacturability. Indium-Gallium-Zinc-Oxide (IGZO) is a semiconductor material which is at the onset of commercialization. The low-temperature large-area deposition compatibility of IGZO makes it an attractive technology from a manufacturing standpoint, with an electron mobility that is 10 times higher than current amorphous silicon technology. The stability of IGZO TFTs continues to be a challenge due to the presence of defect states and problems associated with interface passivation. The goal of this dissertation is to further the understanding of the role of defect states in IGZO, and investigate materials and processes needed to regulate defects to the level at which the associated influence on device operation is controlled. The relationships between processes associated with IGZO TFT operation including IGZO sputter deposition, annealing conditions and back-channel passivation are established through process experimentation, materials analysis, electrical characterization, and modeling of electronic properties and transistor behavior. Each of these components has been essential in formulating and testing several hypotheses on the mechanisms involved, and directing efforts towards achieving the goal. Key accomplishments and quantified results are summarized as follows: XPS analysis identified differences in oxygen vacancies in samples before and after oxidizing ambient annealing at 400 °C, showing a drop in relative integrated area of the O 1s peak from 32% to 19%, which experimentally translates to over a thousand fold decrease in the channel free electron concentration. Transport behavior at cryogenic temperatures identified variable range hopping as the electron transport mechanism at temperature below 130 K, whereas at temperature greater than 130 K, the current vs temperature response followed an Arrhenius relationship consistent with extended state transport. Refinement of an IGZO material model for TCAD simulation, which consists of oxygen vacancy donors providing an integrated space charge concentration NVO = +5e15 cm-3, and acceptor-like band-tail states with a total integrated ionized concentration of NTA = -2e18 cm-3. An intrinsic electron mobility was established to be Un = 12.7 cm2/V∙s. A SPICE-compatible 2D on-state operation model for IGZO TFTs has been developed which includes the integration of drain-impressed deionization of band-tail states and results in a 2D modification of free channel charge. The model provides an exceptional match to measured data and TCAD simulation, with model parameters for channel mobility (Uch = 12 cm2/V∙s) and threshold voltage (VT = 0.14 V) having a close match to TCAD analogs. TCAD material and device models for bottom-gate and double-gate TFT configurations have been developed which depict the role of defect states on device operation, as well as provide insight and support of a presented hypothesis on DIBL like device behavior associated with back-channel interface trap inhomogeneity. This phenomenon has been named Trap Associated Barrier Lowering (TABL). A process integration scheme has been developed that includes IGZO back-channel passivation with PECVD SiO2, furnace annealing in O2 at 400 °C, and a thin capping layer of alumina deposited via atomic layer deposition. This process supports device stability when subjected to negative and positive bias stress conditions, and thermal stability up to 140 °C. It also enables TFT operation at short channel lengths (Leff ~ 3 μm) with steep subthreshold characteristics (SS ~ 120 mV/dec). The details of these contributions in the interpretation and regulation of electronic defect states in IGZO TFTs is presented, along with the support of device characteristics that are among the best reported in the literature. Additional material on a complementary technology which utilizes flash-lamp annealing of amorphous silicon will also be described. Flash-Lamp Annealed Polycrystalline Silicon (FLAPS) has realized n-channel and p-channel TFTs with promising results, and may provide an option for future applications with the highest performance demands. IGZO is rapidly emerging as the candidate to replace a-Si:H and address the performance needs of display products produced by large panel manufacturing."--Abstract.