Advanced Technologies For Improving High Frequency Performance Of Algan Gan High Electron Mobility Transistors
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Advanced Technologies For Improving High Frequency Performance Of Algan Gan High Electron Mobility Transistors
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Author : Jinwook Will Chung
language : en
Publisher:
Release Date : 2008
Advanced Technologies For Improving High Frequency Performance Of Algan Gan High Electron Mobility Transistors written by Jinwook Will Chung and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008 with categories.
In this thesis, we have used a combination of physical analysis, numerical simulation and experimental work to identify and overcome some of the main challenges in AlGaN/GaN high electron mobility transistors (HEMTs) for high frequency applications. In spite of their excellent material properties, GaN-based HEMTs are still below the theoretical predictions in their high frequency performance. If the frequency performance could be improved, the superior breakdown characteristics of nitride semiconductors would make these devices the best option for power amplifiers at any frequency. To achieve this goal, we have first identified some critical parameters that limit the high frequency performance of AlGaN/GaN HEMTs and then we have demonstrated several new technologies to increase the performance. Some of these technologies include advanced drain delay engineering, charge control in the channel and new N-face GaN HEMTs. Although more work is needed in the future to combine all these new technologies, the initial results are extremely promising.
Millimeter Wave Gan High Electron Mobility Transistors And Their Integration With Silicon Electronics
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Author : Jinwook Will Chung
language : en
Publisher:
Release Date : 2011
Millimeter Wave Gan High Electron Mobility Transistors And Their Integration With Silicon Electronics written by Jinwook Will Chung and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
In spite of the great progress in performance achieved during the last few years, GaN high electron mobility transistors (HEMTs) still have several important issues to be solved for millimeter-wave (30 ~ 300 GHz) applications. One of the key challenges is to improve its high frequency characteristics. In this thesis, we particularly focus on fT and fma, two of the most important figures of merit in frequency performance of GaN HEMTs and investigate them both analytically and experimentally. Based on an improved physical understanding and new process technologies, we aim to demonstrate the state-of-the-art high frequency performance of GaN HEMTs. To maximize fmax, parasitic components in the device (Ri, R, Rg, Cgd, and go) are carefully minimized and the optimized 60-nm AlGaN/GaN HEMT shows a very high fmax of 300 GHz. The lower-than-expected fT observed in many AlGaN/GaN HEMTs is attributed to a significant drop of the intrinsic transconductance at high frequency (RF gm) with respect to the intrinsic DC g. (called RF gm-collapse). By suppressing RF gm-collapse and harmoniously scaling the device, a record fT of 225 GHz is achieved in the 55-nm AlGaN/GaN HEMT. Another important challenge for the wide adoption of GaN devices is to develop suitable technology to integrate these GaN transistors with Si(100) electronics. In this thesis, we demonstrate a new technology to integrate, for the first time, GaN HEMTs and Si(100) MOSFETs on the same chip. This integration enables the development of hybrid circuits that take advantage of the high-frequency and power capability of GaN and the unsurpassed circuit scalability and complexity of Si electronics.
Advanced Channel Engineering In Iii Nitride Hemts For High Frequency Performance
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Author : Pil Sung Park
language : en
Publisher:
Release Date : 2013
Advanced Channel Engineering In Iii Nitride Hemts For High Frequency Performance written by Pil Sung Park and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
Abstract: In this thesis, we have investigated and overcome the major limiting factors of intrinsic and parasitic parameters in III-Nitride high electron mobility transistors for high frequency performance with a combined study of simulations and experimental work. The high frequency RF performance of these transistors is severely degraded when short-channel effects, and parasitic resistances are present. To investigate short-channel effects, first, we have developed a simulation model for Ga-polar and N-polar HEMT structures, and found the main reasons for these degradations are drain-induced barrier-lowering and space-charge-limited current injection. To mitigate this, a strong electrostatic back-barrier structure from N-polar orientation is suggested. Secondly, the effect of quantum displacement in GaN HEMTs were investigated using both simulation and experimental measurements. It was discovered that the quantum displacement in a highly scaled device can give more than 2x change in the gate-source capacitance between two different orientations. Therefore it is imperative that the device design for such highly scaled devices consider quantum displacement effects in order to avoid short-channel effects. Another limiting factor from extrinsic elements is the parasitic resistances, especially from contact resistance. To achieve low-resistance non-alloyed Ohmic contacts, we developed two new process technologies that included an inserted graphene layer between metal and AlGaN, and a graded n+ AlGaN Ohmic layer. Both approaches utilized the current path where no barrier exists. In this work, we set the record low contact resistance of 0.049 Ohm mm for Ga-polar technology using the graded AlGaN scheme. The most crucial factor for improving high frequency performance for III-Nitride HEMTs is the saturation of the effective electron velocity. We have modeled the velocity saturation in GaN channel based on LO phonon emission, and explain the phenomena of rapidly decreasing behavior transconductance. This model was also applied to 2-D device simulation where it was possible to obtain the DC and RF characteristics matching to the experimental results. To overcome the fast reduction in gm and fT, we have introduced a polarization graded channel in AlGaN/GaN HEMT and graded AlGaN HFET to tailor the charge profile, and demonstrated a flat gm profile for the first time in field-effect-transistor structure. The high frequency performance of this engineered channel was measured from a highly scaled graded AlGaN HFET with advanced process technology including contact layer regrowth and e-beam lithography. Although the flat gm improved the linearity of fT and fmax, they do not stay flat due to an increasing capacitance profile in a regular 2 X 50 micrometre device. With further scaling of the device width, we obtained an increasing gm profile which can compensate the increment of capacitance, and finally we demonstrated flat fT and fmax profile which has been unseen in any field-effect-transistors. All these results shown in this thesis can contribute to further improvements in high frequency and high power performance of III-Nitride HEMTs for the future RF application beyond mm-Wave frequency.
Modeling Of Algan Gan High Electron Mobility Transistor For Sensors And High Temperature Circuit Applications
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Author : Sazia Afreen Eliza
language : en
Publisher:
Release Date : 2008
Modeling Of Algan Gan High Electron Mobility Transistor For Sensors And High Temperature Circuit Applications written by Sazia Afreen Eliza and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008 with categories.
With the most advanced and mature technology for electronic devices, silicon (Si) based devices can be processed with practically no material defects. However, Si technology has difficulty meeting the demand for some high-power, high-speed, and high-temperature applications due to limitations in its intrinsic properties. Wide bandgap semiconductors have greater prospects compared to Si based devices. The wide band gap material system shows higher breakdown voltage, lower leakage, higher saturation velocity, larger thermal conductivity and better thermal stability suitable for high-power, high-speed, and high-temperature operations of the devices. In recent years, GaN based devices have drawn much research attention due to their superior performances compared to other wide bandgap semiconductor (SiC) devices. Specifically, implementation of AlGaN/GaN high electron mobility transistor (HEMT) based power amplifiers have become very promising for applications in base stations or radar. With the increase in device power, channel temperature rises. This introduces high-temperature effects in the device characteristics. In addition, high-power, high-frequency and high-temperature operation of AlGaN/GaN HEMT is required for telemetry in extreme environment. AlGaN/GaN HEMT also shows great potential as chemically selective field-effect transistor (CHEMFET). Due to simpler imprint technique and amplification advantages CHEMFET based detection and characterization of bio-molecules has become very popular. AlGaN/GaN HEMT has high mobility two-dimensional electron gas (2 DEG) at the hetero-interface closer to the surface and hence it shows high sensitivity to any surface charge conditions. The primary objective of this research is to develop a temperature dependent physics based model of AlGaN/GaN HEMT to predict the performance for high-power and high-speed applications at varying temperatures. The physics based model has also been applied to predict the characteristics of AlGaN/GaN HEMT based CHEMFET for the characterization of bio-molecular solar batteries - Photosystem I reaction centers. Using the CHEMFET model, the number of reaction centers with effective orientation on the gate surface of the HEMT can be estimated.
Electrical And Electronic Devices Circuits And Materials
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Author : Suman Lata Tripathi
language : en
Publisher: John Wiley & Sons
Release Date : 2021-03-24
Electrical And Electronic Devices Circuits And Materials written by Suman Lata Tripathi and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-03-24 with Technology & Engineering categories.
The increasing demand for electronic devices for private and industrial purposes lead designers and researchers to explore new electronic devices and circuits that can perform several tasks efficiently with low IC area and low power consumption. In addition, the increasing demand for portable devices intensifies the call from industry to design sensor elements, an efficient storage cell, and large capacity memory elements. Several industry-related issues have also forced a redesign of basic electronic components for certain specific applications. The researchers, designers, and students working in the area of electronic devices, circuits, and materials sometimesneed standard examples with certain specifications. This breakthrough work presents this knowledge of standard electronic device and circuit design analysis, including advanced technologies and materials. This outstanding new volume presents the basic concepts and fundamentals behind devices, circuits, and systems. It is a valuable reference for the veteran engineer and a learning tool for the student, the practicing engineer, or an engineer from another field crossing over into electrical engineering. It is a must-have for any library.
Handbook For Iii V High Electron Mobility Transistor Technologies
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Author : D. Nirmal
language : en
Publisher: CRC Press
Release Date : 2019-05-14
Handbook For Iii V High Electron Mobility Transistor Technologies written by D. Nirmal and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-05-14 with Science categories.
This book focusses on III-V high electron mobility transistors (HEMTs) including basic physics, material used, fabrications details, modeling, simulation, and other important aspects. It initiates by describing principle of operation, material systems and material technologies followed by description of the structure, I-V characteristics, modeling of DC and RF parameters of AlGaN/GaN HEMTs. The book also provides information about source/drain engineering, gate engineering and channel engineering techniques used to improve the DC-RF and breakdown performance of HEMTs. Finally, the book also highlights the importance of metal oxide semiconductor high electron mobility transistors (MOS-HEMT). Key Features Combines III-As/P/N HEMTs with reliability and current status in single volume Includes AC/DC modelling and (sub)millimeter wave devices with reliability analysis Covers all theoretical and experimental aspects of HEMTs Discusses AlGaN/GaN transistors Presents DC, RF and breakdown characteristics of HEMTs on various material systems using graphs and plots
Processing And Characterization Of Advanced Algan Gan Heterojunction Effect Transistors
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Author : Jaesun Lee
language : en
Publisher:
Release Date : 2006
Processing And Characterization Of Advanced Algan Gan Heterojunction Effect Transistors written by Jaesun Lee and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with Heterostructures categories.
Abstract: AlGaN/GaN high electron mobility transistors (HEMTs) have demonstrated high current levels, high breakdown voltages, and high frequency power performance due to its unique material properties. The further improvements of AlGaN/GaN HEMTs rely on the improvement of material quality and further reduction of parasitic resistance. The purpose of this study is to fabricate and characterize AlGaN/GaN HEMTs for high frequency and high power applications. The first focus of this research is to investigate the post-gate annealing effect on the direct current and radio frequency device performances. Post-gate annealing of AlGaN/GaN turns out to be one of the simple and effective techniques to improve breakdown voltage and power performance of devices dramatically. Especially, after post-annealing at 400 0C for 10 minutes, the maximum drain current at a gate bias of 1 V increases from 823 mA/mm to 956 mA/mm. The transconductance of the devices was improved from 223 mS/mm to 233 mS/mm. The breakdown voltages of the devices were enhanced remarkably from 25 V to 187 V. The threshold voltage exhibited a negative shift. The values fT and fMAX increase from 24 GHz and 80 GHz to 55 GHz and 150 GHz, respectively. The output power and associated gain at 10 GHz are improved from 16.4 dBm and 11.4 dB to 25.9 dBm and 19 dB, respectively. The power added efficiency (PAE) is improved from 29.4 to 52.5 %. The second focus is to develop self-aligned AlGaN/GaN HEMTs, which are very attractive because of the minimized source access resistance. However, the thick metal scheme and high processing temperature of ohmic contacts on III-nitrides hinder the realization of self-aligned devices. In this study, self-aligned AlGaN/GaN high electron mobility transistors are fabricated and characterized with the thin metal schemes of Ti/Al/Ti/Au and Mo/Al/Mo/Au for gate to source and drain self-alignment. Thin Mo/Al/Mo/Au metal layer show good ohmic contact behavior even after annealed for 5 minutes at 600 0C in a furnace while thin ohmic metal scheme of Ti/Al/Ti/Au does not produce ohmic contact even after annealed at 750 0C for 30 minutes. The third focus is to develop the enhancement mode AlGaN/GaN HEMTs. Quasi-enhancement mode AlGaN/GaN HEMT devices with 1-um gate length are fabricated. These quasi-enhancement mode devices exhibit the threshold voltage of as low as - 0.3 V, a gm of 140 mS/mm, an fT of 4.3 GHz, and an fMAX of 13.3 GHz, respectively. Further improvement of enhancement-mode GaN-based HEMT devices is desired for applications of complementary integrated circuits.
Iii Nitride Transistors For High Linearity Rf Applications
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Author : Md Shahadat Hasan Sohel
language : en
Publisher:
Release Date : 2020
Iii Nitride Transistors For High Linearity Rf Applications written by Md Shahadat Hasan Sohel and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with Modulation-doped field-effect transistors categories.
This dissertation investigates new approaches to improve the linearity performance of III-Nitride high-frequency transistors. Next-generation communication technologies require significantly better linearity performance from power amplifiers, and new design approaches are necessary to achieve higher power amplifier linearity at high frequency. Currently, AlGaN/GaN high electron mobility transistor (HEMT) based power amplifiers are preferred choice for high power high frequency applications. However, they suffer from gain suppression resulting from non-linear transconductance characteristics. Transconductance (gm) drop-off at high currents is one of the major sources of non-linearity in HEMTs. A three-dimensional electron channel from compositional grading of the AlGaN is found to create a constant transconductance profile by enabling constant sheet charge density and saturation velocity of carriers in the channel over a wide range of gate bias conditions. Composite channels that combine 2-dimensional (2D) and 3-dimensional (3D) electron channels could also enable improved linearity performance. Large signal simulations to predict the power and linearity performance of transistors for arbitrary epitaxial design transistors were developed. The large signal simulations show significantly improved linearity performance in polarization-graded field effect transistors (PolFETs) and composite 2D-3D channel transistors when compared with conventional AlGaN/GaN HEMTs. Graded channel transistors were found to be limited by DC-RF dispersion resulting from poor surface passivation. To improve the DC-RF dispersion, low-pressure chemical vapor deposition (LPCVD)-based SiNx passivation was used, leading to significant improvement in the dispersion characteristics, and excellent linearity figure ore merit (OIP3/PDC) of 13.3 dB. In addition to dielectric passivation, to address the surface dispersion, epitaxial passivation of cap layers was also investigated, leading to nearly dispersion-free behavior for the graded channel transistors. As an alternative approach to achieve high linearity performance, III-Nitride bipolar junction transistors were investigated. A new device design is proposed based on a laterally patterned base that enables variable injection of current from emitter to the base in order to improve the base conductivity without sacrificing the injection efficiency. With this new technique, a high emitter current density of 55 kA/cm2 was achieved in an npn GaN bipolar transistor. The results presented in this thesis demonstrate an excellent potential for III-Nitride transistor as high linearity transistors required for next generation communic
Wide Bandgap Semiconductor Electronics And Devices
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Author : Uttam Singisetti
language : en
Publisher: World Scientific
Release Date : 2019-12-10
Wide Bandgap Semiconductor Electronics And Devices written by Uttam Singisetti and has been published by World Scientific this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-12-10 with Technology & Engineering categories.
'This book is more suited for researchers already familiar with WBS who are interested in developing new WBG materials and devices since it provides the latest developments in new materials and processes and trends for WBS and UWBS technology.'IEEE Electrical Insulation MagazineWith the dawn of Gallium Oxide (Ga2O₃) and Aluminum Gallium Nitride (AlGaN) electronics and the commercialization of Gallium Nitride (GaN) and Silicon Carbide (SiC) based devices, the field of wide bandgap materials and electronics has never been more vibrant and exciting than it is now. Wide bandgap semiconductors have had a strong presence in the research and development arena for many years. Recently, the increasing demand for high efficiency power electronics and high speed communication electronics, together with the maturity of the synthesis and fabrication of wide bandgap semicon-ductors, has catapulted wide bandgap electronics and optoelectronics into the mainstream.Wide bandgap semiconductors exhibit excellent material properties, which can potentially enable power device operation at higher efficiency, higher temperatures, voltages, and higher switching speeds than current Si technology. This edited volume will serve as a useful reference for researchers in this field — newcomers and experienced alike.This book discusses a broad range of topics including fundamental transport studies, growth of high-quality films, advanced materials characterization, device modeling, high frequency, high voltage electronic devices and optical devices written by the experts in their respective fields. They also span the whole spectrum of wide bandgap materials including AlGaN, Ga2O₃and diamond.
Advanced Nanoscale Mosfet Architectures
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Author : Kalyan Biswas
language : en
Publisher: John Wiley & Sons
Release Date : 2024-05-29
Advanced Nanoscale Mosfet Architectures written by Kalyan Biswas and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2024-05-29 with Technology & Engineering categories.
Comprehensive reference on the fundamental principles and basic physics dictating metal–oxide–semiconductor field-effect transistor (MOSFET) operation Advanced Nanoscale MOSFET Architectures provides an in-depth review of modern metal–oxide–semiconductor field-effect transistor (MOSFET) device technologies and advancements, with information on their operation, various architectures, fabrication, materials, modeling and simulation methods, circuit applications, and other aspects related to nanoscale MOSFET technology. The text begins with an introduction to the foundational technology before moving on to describe challenges associated with the scaling of nanoscale devices. Other topics covered include device physics and operation, strain engineering for highly scaled MOSFETs, tunnel FET, graphene based field effect transistors, and more. The text also compares silicon bulk and devices, nanosheet transistors and introduces low-power circuit design using advanced MOSFETs. Additional topics covered include: High-k gate dielectrics and metal gate electrodes for multi-gate MOSFETs, covering gate stack processing and metal gate modification Strain engineering in 3D complementary metal-oxide semiconductors (CMOS) and its scaling impact, and strain engineering in silicon–germanium (SiGe) FinFET and its challenges and future perspectives TCAD simulation of multi-gate MOSFET, covering model calibration and device performance for analog and RF applications Description of the design of an analog amplifier circuit using digital CMOS technology of SCL for ultra-low power VLSI applications Advanced Nanoscale MOSFET Architectures helps readers understand device physics and design of new structures and material compositions, making it an important resource for the researchers and professionals who are carrying out research in the field, along with students in related programs of study.