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Gan Hemt Modeling Including Trapping Effects Based On Chalmers Model And Pulsed S Parameter Measurements
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Book Synopsis GaN HEMT Modeling Including Trapping Effects Based on Chalmers Model and Pulsed S-Parameter Measurements by : Peng Luo
Download or read book GaN HEMT Modeling Including Trapping Effects Based on Chalmers Model and Pulsed S-Parameter Measurements written by Peng Luo and published by Cuvillier Verlag. This book was released on 2019-01-09 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: GaN HEMTs are regarded as one of the most promising RF power transistor technologies thanks to their high-voltage high-speed characteristics. However, they are still known to be prone to trapping effects, which hamper achievable output power and linearity. Hence, accurately and efficiently modeling the trapping effects is crucial in nonlinear large-signal modeling for GaN HEMTs. This work proposes a trap model based on Chalmers model, an industry standard large-signal model. Instead of a complex nonlinear trap description, only four constant parameters of the proposed trap model need to be determined to accurately describe the significant impacts of the trapping effects, e.g., drain-source current slump, typical kink observed in pulsed I/V characteristics, and degradation of the output power. Moreover, the extraction procedure of the trap model parameters is based on pulsed S-parameter measurements, which allow to freeze traps and isolate the trapping effects from self-heating. The model validity is tested through small- and large-signal model verification procedures. Particularly, it is shown that the use of this trap model enables to dramatically improve the large-signal simulation results.
Book Synopsis Parameter Extraction and Complex Nonlinear Transistor Models by : Gunter Kompa
Download or read book Parameter Extraction and Complex Nonlinear Transistor Models written by Gunter Kompa and published by Artech House. This book was released on 2019-12-31 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt: All model parameters are fundamentally coupled together, so that directly measured individual parameters, although widely used and accepted, may initially only serve as good estimates. This comprehensive resource presents all aspects concerning the modeling of semiconductor field-effect device parameters based on gallium-arsenide (GaAs) and gallium nitride (GaN) technology. Metal-semiconductor field-effect transistors (MESFETs), high electron mobility transistors (HEMTs) and heterojunction bipolar transistors (HBTs), their structures and functions, and existing transistor models are also classified. The Shockley model is presented in order to give insight into semiconductor field-effect transistor (FET) device physics and explain the relationship between geometric and material parameters and device performance. Extraction of trapping and thermal time constants is discussed. A special section is devoted to standard nonlinear FET models applied to large-signal measurements, including static-/pulsed-DC and single-/two-tone stimulation. High power measurement setups for signal waveform measurement, wideband source-/load-pull measurement (including envelope source-/load pull) are also included, along with high-power intermodulation distortion (IMD) measurement setup (including envelope load-pull). Written by a world-renowned expert in the field, this book is the first to cover of all aspects of semiconductor FET device modeling in a single volume.
Book Synopsis A deep ultraviolet laser light source by frequency doubling of GaN based external cavity diode laser radiation by : Norman Ruhnke
Download or read book A deep ultraviolet laser light source by frequency doubling of GaN based external cavity diode laser radiation written by Norman Ruhnke and published by Cuvillier Verlag. This book was released on 2022-05-13 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: A compact and portable laser light source emitting in the wavelength range between 210 nm and 230 nm would enable numerous applications outside of laboratory environments, such as sterilization and disinfection of medical equipment, water purification or gas and air analysis using absorption spectroscopy. Such a source is also highly attractive for the identification and quantification of proteins and biomolecules by means of laser-induced fluorescence or Raman spectroscopy. In this thesis, a novel concept to realize such a compact and portable laser light source with low power consumption and an emission around 222 nm is investigated. The developed concept is based on single-pass frequency doubling of a commercially available high-power GaN laser diode emitting in the blue spectral range. Due to the low frequency doubling conversion efficiencies in this wavelength range of about 10-4 W-1, a laser diode with high optical output power above 1 W is required as pump source. Moreover, it has to exhibit narrowband emission in the range of the acceptance bandwidth of the applied nonlinear BBO crystal. Since GaN-based high-power laser diodes typically show broad emission spectra of Δλ = 1…2 nm, stabilizing and narrowing their wavelength by using external wavelength-selective elements is investigated and presented for the first time. With the understanding for the novel concept gained in this work, a compact ultraviolet laser light source was realized. It has a power consumption of less than 10 W and is exceptionally robust due to its immoveable components. The demonstrated output power of 160 μW enables numerous industrial and everyday applications for which previous laser systems have been too complex and overly cost- and energy-intensive.
Book Synopsis Design, simulation and analysis of laterally-longitudinally non-uniform edge-emitting GaAs-based diode lasers (Band 73) by : Jan-Philipp Koester
Download or read book Design, simulation and analysis of laterally-longitudinally non-uniform edge-emitting GaAs-based diode lasers (Band 73) written by Jan-Philipp Koester and published by Cuvillier Verlag. This book was released on 2023-09-19 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Edge-emitting quantum-well diode lasers based on GaAs combine a high conversion efficiency, a wide range of emission wavelengths covering a span from 630 nm to 1180 nm, and the ability to achieve high output powers. The often used longitudinal-invariant Fabry-Pérot-type resonators are easy to design but often lead to functionality or performance limitations. In this work, the application of laterally-longitudinally non-uniform resonator configurations is explored as a way to reduce unwanted and performance-limiting effects. The investigations are carried out on existing and entirely newly developed laser designs using dedicated simulation tools. These include a sophisticated time-dependent laser simulator based on a traveling-wave model of the optical fields in the lateral-longitudinal plane and a Maxwell solver based on the eigenmode expansion method for the simulation of passive waveguides. Whenever possible, the simulation results are compared with experimental data. Based on this approach, three fundamentally different laser types are investigated: • Dual-wavelength lasers emitting two slightly detuned wavelengths around 784 nm out of a single aperture • Ridge-waveguide lasers with tapered waveguide and contact layouts that emit light of a wavelength of around 970 nm • Broad-area lasers with slightly tapered contact layouts emitting at 910 nm The results of this thesis underline the potential of lateral-longitudinal non-uniform laser designs to increase selected aspects of device performance, including beam quality, spectral stability, and output power.
Book Synopsis AlN base layers for UV LEDs by : Sebastian Walde
Download or read book AlN base layers for UV LEDs written by Sebastian Walde and published by Cuvillier Verlag. This book was released on 2021-06-22 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: To enable the fabrication of high performance ultraviolet (UV) light-emitting diodes (LEDs) this work aims at improving the quality of AlN base layers on sapphire substrates. The main issues for UV LEDs are still a limited internal quantum efficiency due to a high amount of threading dislocations along with a limited light extraction efficiency due to total internal reflection at the AlN/sapphire interface. Therefore, high-temperature annealing of AlN/sapphire layers and growth on nanopatterned sapphire substrates were comprehensively investigated. High-temperature annealing was applied to AlN layers of different strain and thickness grown by metalorganic vapour phase epitaxy (MOVPE). The threading dislocation density could be successfully reduced by more than one order of magnitude down to 6 × 108 cm-2. Wave optical simulations of UV LEDs on nanopatterned sapphire substrates (NPSS) were conducted and showed a potential increase in light extraction efficiency compared to a planar substrate. The optimized MOVPE growth process on sapphire nanopillars and sapphire nanoholes resulted in a fully coalesced and atomically smooth AlN surface. The threading dislocation density was reduced to 1 ×109 cm-2 for AlN on both nanopillars and nanoholes. UVC LEDs emitting at 265 nm wavelength were grown on top of the developed templates. Increased internal efficiency was obtained by reduced dislocation density and more efficient light extraction was achieved on NPSS in case of a transparent heterostructure and reflective contacts. Thus, the developed templates yield considerable improvement in light output compared to conventional templates.
Book Synopsis Two-step MOVPE, in-situ etching and buried implantation: applications to the realization of GaAs laser diodes by : Pietro della Casa
Download or read book Two-step MOVPE, in-situ etching and buried implantation: applications to the realization of GaAs laser diodes written by Pietro della Casa and published by Cuvillier Verlag. This book was released on 2021-03-25 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is about two-step epitaxial growth using metalorganic vapor-phase epitaxy (MOVPE) for the realization of edge-emitting near-infrared laser diodes. The fabricated gallium arsenide-based devices fall into two categories: high-power lasers (watt range, multimodal) and tunable lasers (milliwatt range, monomodal). Common to both cases is that surface contamination – particularly that due to oxygen – needs to be removed before regrowth. Thus, in-situ etching with carbon tetrabromide (CBr4) is first studied. The experimental results include kinetic data, the effects of different etching conditions as well as substrate characteristics, and the effectiveness in reducing surface contamination. These investigations pave the way to devices based on 2-step epitaxy combined with in-situ etching. Correspondingly, thermally-tuned SG-DBR lasers operating around 975 nm have been successfully realized, obtaining a tuning range of 21 nm. In addition, the possibility of using electronic tuning in similar devices has been explored. High-power broad-area lasers have also been realized, using two-step epitaxy combined with ex-situ and in-situ etching, to create a buried, shallow “mesa” containing the active zone. This approach allows introducing lateral electrical and optical confinement, and – simultaneously – non-absorbing mirrors at the laser facets. Additionally, a different strategy to create a buried current aperture is presented, which is based on ion implantation followed by epitaxial regrowth. This enables to improve device performance and simultaneously introduce non-absorbing mirrors at the facets with correspondingly increased reliability.
Book Synopsis Spectroscopic Applications of Terahertz Quantum-Cascade Lasers by : Tasmim Alam
Download or read book Spectroscopic Applications of Terahertz Quantum-Cascade Lasers written by Tasmim Alam and published by Cuvillier Verlag. This book was released on 2020-10-29 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum cascade lasers (QCLs) are attractive for high-resolution spectroscopy because they can provide high power and a narrow linewidth. They are particularly promising in the terahertz (THz) range since they can be used as local oscillators for heterodyne detection as well as transmitters for direct detection. However, THz QCL-based technologies are still under development and are limited by the lack of frequency tunability as well as the frequency and output power stability for free-running operation. In this dissertation, frequency tuning and linewidth of THz QCLs are studied in detail by using rotational spectroscopic features of molecular species. In molecular spectroscopy, the Doppler eff ect broadens the spectral lines of molecules in the gas phase at thermal equilibrium. Saturated absorption spectroscopy has been performed that allows for sub-Doppler resolution of the spectral features. One possible application is QCL frequency stabilization based on the Lamb dip. Since the tunability of the emission frequency is an essential requirement to use THz QCL for high-resolution spectroscopy, a new method has been developed that relies on near-infrared (NIR) optical excitation of the QCL rear-facet. A wide tuning range has been achieved by using this approach. The scheme is straightforward to implement, and the approach can be readily applied to a large class of THz QCLs. The frequency and output stability of the local oscillator has a direct impact on the performance and consistency of the heterodyne spectroscopy. A technique has been developed for a simultaneous stabilization of the frequency and output power by taking advantage of the frequency and power regulation by NIR excitation. The results presented in this thesis will enable the routine use of THz QCLs for spectroscopic applications in the near future.
Book Synopsis Analysis of Spatio-Temporal Phenomena in High-Brightness Diode Lasers using Numerical Simulations by : Anissa Zeghuzi
Download or read book Analysis of Spatio-Temporal Phenomena in High-Brightness Diode Lasers using Numerical Simulations written by Anissa Zeghuzi and published by Cuvillier Verlag. This book was released on 2020-10-22 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Broad-area lasers are edge-emitting semiconductor lasers with a wide lateral emission aperture. This feature enables high output powers but also diminishes the lateral beam quality and results in their inherently non-stationary behavior. Research in the area is driven by application, and the main objective is to increase the brightness, which includes both output power and lateral beam quality. To understand the underlying spatio-temporal phenomena and to apply this knowledge in order to reduce costs for brightness optimization, a self-consistent simulation tool taking all essential processes into account is vital. Firstly, in this work a quasi-three-dimensional opto-electronic and thermal model is presented that describes essential qualitative characteristics of real devices well. Time-dependent traveling-wave equations are utilized to characterize the inherently non-stationary optical fields, which are coupled to dynamic rate equations for the excess carriers in the active region. This model is extended by an injection-current-density model to accurately include lateral current spreading and spatial hole burning. Furthermore, a temperature model is presented that includes short-time local heating near the active region as well as the formation of a stationary temperature profile. Secondly, the reasons of brightness degradation, i.e. the origins of power saturation and the spatially modulated field profile, are investigated. And lastly, designs that mitigate those effects limiting the lateral brightness under pulsed and continuous-wave operation are discussed. Amongst those designs a novel “chessboard laser” is presented that utilizes longitudinal-lateral gain-loss modulation and an additional phase tailoring to obtain a very low far-field divergence.
Book Synopsis Transceiver Technologies for Millimeter-Wave Beam Steering Applications (Band 71) by : Yi-Fan Tsao
Download or read book Transceiver Technologies for Millimeter-Wave Beam Steering Applications (Band 71) written by Yi-Fan Tsao and published by Cuvillier Verlag. This book was released on 2022-11-08 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the past years, wireless communication systems have been rapidly advancing to meet the high data-rate requirements of various emerging applications. However, the existing transceivers have typically been demonstrated using CMOS-compatible technologies that deliver a relatively low equivalent isotropic radiated power in a small unit cell. Moreover, the particular device characteristics are limiting the linear region for operation. Therefore, the main focus of this dissertation is to present and discuss new design methods for transceivers to solve these issues. To reduce the complexity of the transceiver module for further phased-array scaling, a low-noise power amplifier design approach is designed using a 0.15-μm GaN-on-SiC high-electron mobility transistor technology (HEMT). Utilizing a traded off interstage matching topology between loss and bandwidth, the conversion loss induced by the matching network could be effectively reduced. A stacked-FET configuration was adopted to enhance the power handling of the RF switch. Further improvement on the isolation bandwidth was investigated using theoretical analysis on the intrinsic effect of the passive HEMTs. With the successful implementation of the RF front-end circuits, transceiver modules were integrated on Rogers RO3010 substrate. The planar dual exponentially tapered slot antenna phased-array system showed a compact size with simple biasing network compared to the conventional transceiver approach. The presented T/R module was characterized with an over-the-air test at a distance of 1 m, overcoming the free space path loss of 64 dB. It also shows a high flexibility for further integration with a larger number of array systems, which is very promising for future 5G communication systems.
Book Synopsis Broad-Area Laser Bars for 1 kW-Emission by : Matthias M. Karow
Download or read book Broad-Area Laser Bars for 1 kW-Emission written by Matthias M. Karow and published by Cuvillier Verlag. This book was released on 2022-06-27 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: ndustrial laser systems for material processing applications rely on the availability of highly efficient, high-brightness diode lasers. GaAs-based broad-area laser bars play a vital role in such applications as pump sources for high-beam-quality solid-state lasers and, increasingly, as direct processing tools. This work studies 940 nm-laser bars emitting 1 kW optical power at room temperature, identifying those physical mechanisms that are currently limiting electrical-to-optical conversion efficiency as well as lateral beam quality. In the process, several diagnostic studies on bars with varied lateral-longitudinal design were carried out. The effects of technological measures for performance optimization were analyzed, yielding a new benchmark in efficiency and lateral divergence. The studies into altered resonator lengths of 4 and 6 mm as well as fill factors between 69 and 87 % successfully reduce both the voltage dropping across the device and power saturation at high currents, enabling 66 % efficiency at the operation point. Concrete measures how to reach efficiencies ≥70 % are presented thereafter, showing that doubling the efficiency value of the first 1 kW-demonstration in 2007 – amounting to 35 % – is in near reach. Investigation of the beam quality bases on a herein proposed and realized concept, in which the far field is resolved for each individual bar emitter. In this way, it is possible to determine how far-field profiles vary along the bar width and how much these variations affect the overall bar far-field. Further, such effects specific to bar structures can be separated into non-thermal and thermal influences. The effect of mechanical chip deformation (bar smile) as well as neighboring-emitter interaction has been investigated for the first time in active kW-class devices, yielding a lateral divergence as low as 8.8° at the operation point.
Book Synopsis Advanced Large-Signal Modeling of GaN-HEMTs by : M. Berroth
Download or read book Advanced Large-Signal Modeling of GaN-HEMTs written by M. Berroth and published by . This book was released on 2002 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: For improved non-linear modeling of AlGaN/GaN high electron mobility transistors, a large- signal model originally developed for GaAs-based devices has been extended by introduction of a thermal sub-circuit to account for self-heating. Thereby, DC output characteristics which typically show negative output conductance at a high dissipating power level are well reproduced. Since self-heating also effects the transconductance, which is related to S(sub 21 at RF conditions, the comparison of broadband S-parameter simulations and measurements revealed significant improvement when using the extended model. First experimental and theoretical investigations on the transient behavior at pulsed conditions are finally presented.
Book Synopsis Nonlinear Circuit Simulation and Modeling by : José Carlos Pedro
Download or read book Nonlinear Circuit Simulation and Modeling written by José Carlos Pedro and published by Cambridge University Press. This book was released on 2018-06-14 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: A practical, tutorial guide to the nonlinear methods and techniques needed to design real-world microwave circuits.
Book Synopsis Nonlinear Transistor Model Parameter Extraction Techniques by : Matthias Rudolph
Download or read book Nonlinear Transistor Model Parameter Extraction Techniques written by Matthias Rudolph and published by Cambridge University Press. This book was released on 2011-10-13 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: Achieve accurate and reliable parameter extraction using this complete survey of state-of-the-art techniques and methods. A team of experts from industry and academia provides you with insights into a range of key topics, including parasitics, intrinsic extraction, statistics, extraction uncertainty, nonlinear and DC parameters, self-heating and traps, noise, and package effects. Learn how similar approaches to parameter extraction can be applied to different technologies. A variety of real-world industrial examples and measurement results show you how the theories and methods presented can be used in practice. Whether you use transistor models for evaluation of device processing and you need to understand the methods behind the models you use, or you want to develop models for existing and new device types, this is your complete guide to parameter extraction.
Book Synopsis Microwave Circuit Design Using Linear and Nonlinear Techniques by : George D. Vendelin
Download or read book Microwave Circuit Design Using Linear and Nonlinear Techniques written by George D. Vendelin and published by John Wiley & Sons. This book was released on 2005-10-03 with total page 1080 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ultimate handbook on microwave circuit design with CAD. Full of tips and insights from seasoned industry veterans, Microwave Circuit Design offers practical, proven advice on improving the design quality of microwave passive and active circuits-while cutting costs and time. Covering all levels of microwave circuit design from the elementary to the very advanced, the book systematically presents computer-aided methods for linear and nonlinear designs used in the design and manufacture of microwave amplifiers, oscillators, and mixers. Using the newest CAD tools, the book shows how to design transistor and diode circuits, and also details CAD's usefulness in microwave integrated circuit (MIC) and monolithic microwave integrated circuit (MMIC) technology. Applications of nonlinear SPICE programs, now available for microwave CAD, are described. State-of-the-art coverage includes microwave transistors (HEMTs, MODFETs, MESFETs, HBTs, and more), high-power amplifier design, oscillator design including feedback topologies, phase noise and examples, and more. The techniques presented are illustrated with several MMIC designs, including a wideband amplifier, a low-noise amplifier, and an MMIC mixer. This unique, one-stop handbook also features a major case study of an actual anticollision radar transceiver, which is compared in detail against CAD predictions; examples of actual circuit designs with photographs of completed circuits; and tables of design formulae.
Book Synopsis RF and Microwave Power Amplifier Design by : Andrei Grebennikov
Download or read book RF and Microwave Power Amplifier Design written by Andrei Grebennikov and published by McGraw Hill Professional. This book was released on 2004-09-15 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a rigorous tutorial on radio frequency and microwave power amplifier design, teaching the circuit design techniques that form the microelectronic backbones of modern wireless communications systems. Suitable for self-study, corporate training, or Senior/Graduate classroom use, the book combines analytical calculations and computer-aided design techniques to arm electronic engineers with every possible method to improve their designs and shorten their design time cycles.
Book Synopsis Nonlinear Microwave Circuit Design by : Franco Giannini
Download or read book Nonlinear Microwave Circuit Design written by Franco Giannini and published by John Wiley & Sons. This book was released on 2004-06-07 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: Design techniques for nonlinear microwave circuits are much less developed than for linear microwave circuits. Until now there has been no up-to-date text available in this area. Current titles in this field are considered outdated and tend to focus on analysis, failing to adequately address design and measurement aspects. Giannini and Leuzzi provide the theoretical background to non-linear microwave circuits before going on to discuss the practical design and measurement of non-linear circuits and components. Non-linear Microwave Circuit Design reviews all of the established analysis and characterisation techniques available and provides detailed coverage of key modelling methods. Practical examples are used throughout the text to emphasise the design and application focus of the book. * Provides a unique, design-focused, coverage of non-linear microwave circuits * Covers the fundamental properties of nonlinear circuits and methods for device modelling * Outlines non-linear measurement techniques and characterisation of active devices * Reviews available design methodologies for non-linear power amplifiers and details advanced software modelling tools * Provides the first detailed treatment of non-linear frequency multipliers, mixers and oscillators * Focuses on the application potential of non-linear components Practicing engineers and circuit designers working in microwave and communications engineering and designing new applications, as well as senior undergraduates, graduate students and researchers in microwave and communications engineering and their libraries will find this a highly rewarding read.
Book Synopsis Transistor Level Modeling for Analog/RF IC Design by : Wladyslaw Grabinski
Download or read book Transistor Level Modeling for Analog/RF IC Design written by Wladyslaw Grabinski and published by Springer Science & Business Media. This book was released on 2006-07-01 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: The editors and authors present a wealth of knowledge regarding the most relevant aspects in the field of MOS transistor modeling. The variety of subjects and the high quality of content of this volume make it a reference document for researchers and users of MOSFET devices and models. The book can be recommended to everyone who is involved in compact model developments, numerical TCAD modeling, parameter extraction, space-level simulation or model standardization. The book will appeal equally to PhD students who want to understand the ins and outs of MOSFETs as well as to modeling designers working in the analog and high-frequency areas.
