Investigation Of Reliability In Gallium Nitride High Electron Mobility Transistors Using Equivalent Circuit Models For Use In High Power High Frequency Microwave Amplifiers
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Investigation Of Reliability In Gallium Nitride High Electron Mobility Transistors Using Equivalent Circuit Models For Use In High Power High Frequency Microwave Amplifiers
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Author : Benjamin David Huebschman
language : en
Publisher:
Release Date : 2010
Investigation Of Reliability In Gallium Nitride High Electron Mobility Transistors Using Equivalent Circuit Models For Use In High Power High Frequency Microwave Amplifiers written by Benjamin David Huebschman and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.
Reliability Of W Band Inain Gan High Electron Mobility Transistors
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Author : Yufei Wu (Ph. D.)
language : en
Publisher:
Release Date : 2017
Reliability Of W Band Inain Gan High Electron Mobility Transistors written by Yufei Wu (Ph. D.) and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
AlGaN/GaN High Electron Mobility Transistors (HEMTs) have enjoyed tremendous market growth in RF power amplifiers over the past decades. In the quest for enhancing the operating frequency of GaN HEMTs, there has been a great effort to scale down the gate length. Maintaining acceptable short-channel effects requires shrinking the barrier thickness at the same time. However, a limitation exists since there is a minimum barrier thickness that is needed to obtain a sufficiently high two-dimensional electron gas density. One possible solution to this problem is the use of a new barrier material, i.e., InAlN. Due to its high spontaneous polarization, if InAlN is used as a barrier material in GaN HEMTs, a much smaller layer thickness is required compared with conventional HEMTs. This enables further barrier thickness scaling and therefore gate length scaling and a higher frequency response. However, as a relatively new structure, reliability studies of InAlN/GaN HEMTs are still lacking. Solid reliability is essential before the wide commercial deployment of this new technology. This thesis investigates the most relevant degradation mechanisms under important stress regimes, aiming at building a comprehensive understanding of InAIN/GaN HEMT reliability. Through investigating various voltage, current, and temperature stress levels, we have identified one recoverable degradation mechanism as well as three permanent degradation mechanisms. Under high drain voltage, hot-electron trapping results in temporary drain current decrease and drain resistance increase. In addition, under high drain voltage but relatively low drain current level, permanent negative threshold voltage shift and drain current increase have been observed. We attribute the phenomena to dehydrogenation of pre-existing defects in GaN channel by hot electrons. Under high positive gate bias, defect generation in the AIN interlayer due to high electric field across AIN has proven to be responsible for the observed gate leakage current increase. Also, under high-power stress conditions, positive threshold voltage shift and maximum drain current decrease have been consistently observed. We verified through both thermal stress experiments and Transmission Electron Microscopy (TEM) analysis that Schottky gate sinking is the cause. This work provides fundamental understanding of potential reliability concerns in InAlN/GaN HEMTs and is essential in accelerating the future commercialization of this promising technology.
Modeling Gallium Nitride Based High Electron Mobility Transistors
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Author : Ujwal Radhakrishna
language : en
Publisher:
Release Date : 2016
Modeling Gallium Nitride Based High Electron Mobility Transistors written by Ujwal Radhakrishna and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
Gallium-Nitride-based high electron mobility transistor (HEMTs) technology is increasingly finding space in high voltage (HV) and high frequency (HF) circuit application domains. The superior breakdown electric field, high electron mobility, and high temperature performance of GaN HEMTs are the key factors for its use as HV switches in converters and active components of RF-power amplifiers. Designing circuits in both application regimes requires accurate compact device models that are grounded in physics and can describe the non-linear terminal characteristics. Currently available compact models for HEMTs are empirical and hence are lacking in physical description of the device, which becomes a handicap in understanding key device-circuit interactions and in accurate estimation of device behavior in circuits. This thesis seeks to develop a physics-based compact model for GaN HEMTs from first principles which can be used as a design tool for technology optimization to identify device-performance bottlenecks on one hand and as a tool for circuit design to investigate the impact of behavioral nuances of the device on circuit performance, on the other. Part of this thesis consists of demonstrations of the capabilities of the model to accurately predict device characteristics such as terminal DC- and pulsed-currents, charges, small-signal S-parameters, large-signal switching characteristics, load-pull, source-pull and power-sweep, inter-modulation-distortion and noise-figure of both HV- and RF-devices. The thesis also aims to tie device-physics concepts of carrier transport and charge distribution in GaN HEMTs to circuit-design through circuit-level evaluation. In the HV-application regime benchmarking is conducted against switching characteristics of a GaN DC-DC converter to understand the impact of device capacitances, field plates, temperature and charge-trapping on switching slew rates. In the RF-application regime validation is done against the large-signal characteristics of GaN-power amplifiers to study the output-power, efficiency and compression characteristics as function of class-of-operation. Noise-figure of low-noise amplifiers is tested to estimate the contributions of device-level noise sources, and validation against switching frequency and phase-noise characteristics of voltage-controlled oscillators is done to evaluate the noise performance of GaN HEMT technology. Evaluation of model-accuracy in determining the conversion-efficiency of RF-converters and linearity metrics of saturated non-linear amplifiers is carried out. The key contribution of this work is to provide a tool in the form of a physics-based compact model to device-technology-engineers and circuit-designers, who can use it to evaluate the potential strengths and weaknesses of the emerging GaN technology.
Design Of Power Scalable Gallium Nitride Class E Power Amplifiers
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Author : Mark Anthony Connor
language : en
Publisher:
Release Date : 2014
Design Of Power Scalable Gallium Nitride Class E Power Amplifiers written by Mark Anthony Connor and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with Amplifiers, Radio frequency categories.
The need for high power, highly efficient, multi-band and multi-mode radio frequency (RF) and microwave power amplifiers in the commercial and defense wireless industries continues to drive the research and development of gallium nitride (GaN) devices and their implementation in the receiver and transmitter lineups of modern microwave systems. Unlike silicon (Si) or gallium arsenide (GaAs), GaN is a direct wide bandgap semiconductor that permits usage in high voltage and therefore high power applications. Additionally, the increased saturation velocity of GaN allows for operation well into the super high frequency (SHF) portion of the RF spectrum. For the power amplifier designer, active devices utilizing GaN will exhibit power densities almost an order of magnitude greater than comparably sized GaAs devices and almost two orders of magnitude greater than Si devices. Not only does this mean an overall size reduction of an amplifier for a given output power, but it allows GaN to replace specialized components such as the traveling-wave tube (TWT) and other circuits once deemed impossible to realize using solid-state electronics. Designs utilizing GaN in amplifiers, switches, mixers, etc., are able to meet the continually shrinking size, increased power, stringent thermal, and cost requirements of a modern microwave system.There are two relatively straight forward methods used to investigate the intrinsic power scaling properties of a GaN high-electron-mobility transistor (HEMTs) configured as a common source amplifier. The first method involves sweeping the applied drain to source voltage bias and the second method involves scaling the physical size of the transistor. The prior method can be used to evaluate fixed sized transistors while the latter method requires an understanding of the obtainable power density for a given device technology prior to fabrication. Since the power density is also a function of the drain to source voltage bias, an initial iterative component of the design cycle may be required to fully characterize the device technology. If a scalable nonlinear device model is available to the designer, the harmonic balance simulator in most computer aided design (CAD) tools can be used to evaluate device parameters such as the maximum output power and power added efficiency (PAE) using large signal load pull simulations.The circuits presented in this thesis address two power amplifier design approaches commonly used in industry. The first approach utilizes commercially available bare die GaN transistors that can be wire-bonded to matching circuitry on a printed circuit board (PCB). This technique is known as hybrid packaging. The second approach utilizes a fully integrated design or monolithic microwave integrated circuit (MMIC) and the process design kit (PDK) used to design, simulate and layout the power amplifier circuitry before submission to a foundry for fabrication. In both cases, the nonlinear transistor models are used to investigate the power scalability of class E mode GaN power amplifiers and the techniques used to implement such circuits. The design, results, and challenges of each approach are discussed and future work is presented.
Thermal Optimization And Validation Of Gan High Electron Mobility Transistor
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Author : Tanmay Pradip Kavade
language : en
Publisher:
Release Date : 2017
Thermal Optimization And Validation Of Gan High Electron Mobility Transistor written by Tanmay Pradip Kavade and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
Gallium Nitride (GaN) is a binary III/V wide band gap semiconductor used in power electronics for operations at high power densities and high speeds. GaN has excellent characteristics like high break-down voltage, high thermal conductivity, and high electron saturation velocity which have led to an intensive study and wide use of GaN in many fields. Some of these fields range from amplifiers, MMIC, laser diodes, pulsed radars and counter-IED jammers to CAT-V modules and fourth generation infrastructure base-stations. In this study package level thermal analysis and management of GaN high electron mobility transistor was carried out for determination of junction temperature and junction-case thermal resistance (Rjc). Two commercially available models were used as a reference for analysis. The sizes for both the models were 3 x 3 mm and 4 x 4 mm with host substrate SiC and Si respectively. The model considers the thickness of GaN and host substrate layers, the gate pitch, length, width, and thermal conductivity of GaN, and host substrate. The analysis is carried out on FEA software. Initially mesh sensitivity analysis was carried out to determine the best possible grid count for CFD analysis. Both the models were analyzed for steady state condition at various radio frequency power output to map the increment in the junction temperature. A parametric study is being carried out to optimize and reduce the maximum junction temperature and junction to case thermal resistance (Rjc) by providing convective air cooling and heat sink. The other part of this study includes optimization of the model using diamond as the host substrate and ceramic as mold compound material to monitor the decrease in the thermal resistance value. Comparative results in this study show the percentage reduction in the estimated Rjc value. Thermal resistance value is estimated using the below formula, Rjc = Tj - Tc / P From the results obtained a significant reduction in the estimated Rjc value was observed when compared for no flow, air flow with heat-sink, different host substrate and different mold compound material conditions. In conclusion GaN HEMT can be optimized to achieve a significant improvement in operation. This would allow operation of GaN devices at high temperature without damaging the reliability and operation life-span.
Modeling Reliability Of Gallium Nitride High Electron Mobility Transistors
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Author : Balaji Padmanabhan
language : en
Publisher:
Release Date : 2013
Modeling Reliability Of Gallium Nitride High Electron Mobility Transistors written by Balaji Padmanabhan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Couplings categories.
This work is focused on modeling the reliability concerns in GaN HEMT technology. The two main reliability concerns in GaN HEMTs are electromechanical coupling and current collapse. A theoretical model was developed to model the piezoelectric polarization charge dependence on the applied gate voltage. As the sheet electron density in the channel increases, the influence of electromechanical coupling reduces as the electric field in the comprising layers reduces. A Monte Carlo device simulator that implements the theoretical model was developed to model the transport in GaN HEMTs. It is observed that with the coupled formulation, the drain current degradation in the device varies from 2%-18% depending on the gate voltage. Degradation reduces with the increase in the gate voltage due to the increase in the electron gas density in the channel. The output and transfer characteristics match very well with the experimental data. An electro-thermal device simulator was developed coupling the Monte Caro-Poisson solver with the energy balance solver for acoustic and optical phonons. An output current degradation of around 2-3 % at a drain voltage of 5V due to self-heating was observed. It was also observed that the electrostatics near the gate to drain region of the device changes due to the hot spot created in the device from self heating. This produces an electric field in the direction of accelerating the electrons from the channel to surface states. This will aid to the current collapse phenomenon in the device. Thus, the electric field in the gate to drain region is very critical for reliable performance of the device. Simulations emulating the charging of the surface states were also performed and matched well with experimental data. Methods to improve the reliability performance of the device were also investigated in this work. A shield electrode biased at source potential was used to reduce the electric field in the gate to drain extension region. The hot spot position was moved away from the critical gate to drain region towards the drain as the shield electrode length and dielectric thickness were being altered.
Reliability And Failure Analysis Of Gan On Si Power Devices
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Author : Wen Yang
language : en
Publisher:
Release Date : 2021
Reliability And Failure Analysis Of Gan On Si Power Devices written by Wen Yang and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with categories.
Wide bandgap power semiconductor devices, especially Gallium Nitride (GaN) high electron mobility transistors (HEMTs), have gained a lot of attention for high power applications due to their low on-resistance and high switching speed compared to their silicon counterparts. However, the reliability and failure issues related to dynamic performance, gate reliability, and electrostatic discharge have limited the wide applications of GaN power devices. This dissertation presents a systematic study of reliability and failure analysis of GaN-on-Si power devices. Firstly, the correlation between the physical trap mechanisms and the dynamic on-resistance (R[subscript on]) degradation has been investigated using a multi-frequency C-V measurement during pulse-mode stress. The experimental results indicate that the deep-level traps originated from the buffer layer play a dominant role in the dynamic R[subscript on] degradation. Secondly, the Si substrate in GaN-on-Si lateral power devices can be used as an independent contact termination rather than a thermal cooling pad. Therefore, the substrate bias effect in dynamic R[subscript on] and Gate Charge (Q[subscript g]) is necessary to explore both conduction and switching loss in GaN-based converter. A reverse dual polarity (RDP) substrate pulse technique has been developed to mitigate the dynamic R[subscript on] degradation. Thirdly, the gate reliability issues, including Time-dependent dielectric breakdown (TDDB), and Bias Temperature Instability (BTI) have been explored to improve the current capability. The physical model of TDDB in GaN power devices has been established by applying the substrate biases. And three phases of threshold voltage degradation have been presented under Negative Bias Temperature Instability stress. Lastly, the ESD characteristics of GaN power devices are considered for the development of a monolithic GaN-on-Si platform. The breakdown mechanisms under ESD stress have been comprehensively studied using Transmission Line Pulse (TLP) and Very-fast Transmission Line Pulse (VFTLP) measurements.
Power Gan Devices
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Author : Matteo Meneghini
language : en
Publisher: Springer
Release Date : 2016-09-08
Power Gan Devices written by Matteo Meneghini and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016-09-08 with Technology & Engineering categories.
This book presents the first comprehensive overview of the properties and fabrication methods of GaN-based power transistors, with contributions from the most active research groups in the field. It describes how gallium nitride has emerged as an excellent material for the fabrication of power transistors; thanks to the high energy gap, high breakdown field, and saturation velocity of GaN, these devices can reach breakdown voltages beyond the kV range, and very high switching frequencies, thus being suitable for application in power conversion systems. Based on GaN, switching-mode power converters with efficiency in excess of 99 % have been already demonstrated, thus clearing the way for massive adoption of GaN transistors in the power conversion market. This is expected to have important advantages at both the environmental and economic level, since power conversion losses account for 10 % of global electricity consumption. The first part of the book describes the properties and advantages of gallium nitride compared to conventional semiconductor materials. The second part of the book describes the techniques used for device fabrication, and the methods for GaN-on-Silicon mass production. Specific attention is paid to the three most advanced device structures: lateral transistors, vertical power devices, and nanowire-based HEMTs. Other relevant topics covered by the book are the strategies for normally-off operation, and the problems related to device reliability. The last chapter reviews the switching characteristics of GaN HEMTs based on a systems level approach. This book is a unique reference for people working in the materials, device and power electronics fields; it provides interdisciplinary information on material growth, device fabrication, reliability issues and circuit-level switching investigation.
Wide Bandgap Based Devices
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Author : Farid Medjdoub
language : en
Publisher: MDPI
Release Date : 2021-05-26
Wide Bandgap Based Devices written by Farid Medjdoub and has been published by MDPI this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-05-26 with Technology & Engineering categories.
Emerging wide bandgap (WBG) semiconductors hold the potential to advance the global industry in the same way that, more than 50 years ago, the invention of the silicon (Si) chip enabled the modern computer era. SiC- and GaN-based devices are starting to become more commercially available. Smaller, faster, and more efficient than their counterpart Si-based components, these WBG devices also offer greater expected reliability in tougher operating conditions. Furthermore, in this frame, a new class of microelectronic-grade semiconducting materials that have an even larger bandgap than the previously established wide bandgap semiconductors, such as GaN and SiC, have been created, and are thus referred to as “ultra-wide bandgap” materials. These materials, which include AlGaN, AlN, diamond, Ga2O3, and BN, offer theoretically superior properties, including a higher critical breakdown field, higher temperature operation, and potentially higher radiation tolerance. These attributes, in turn, make it possible to use revolutionary new devices for extreme environments, such as high-efficiency power transistors, because of the improved Baliga figure of merit, ultra-high voltage pulsed power switches, high-efficiency UV-LEDs, and electronics. This Special Issue aims to collect high quality research papers, short communications, and review articles that focus on wide bandgap device design, fabrication, and advanced characterization. The Special Issue will also publish selected papers from the 43rd Workshop on Compound Semiconductor Devices and Integrated Circuits, held in France (WOCSDICE 2019), which brings together scientists and engineers working in the area of III–V, and other compound semiconductor devices and integrated circuits. In particular, the following topics are addressed: – GaN- and SiC-based devices for power and optoelectronic applications – Ga2O3 substrate development, and Ga2O3 thin film growth, doping, and devices – AlN-based emerging material and devices – BN epitaxial growth, characterization, and devices
Gallium Nitride
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Author : Dalvir K. Saini
language : en
Publisher:
Release Date : 2015
Gallium Nitride written by Dalvir K. Saini and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with Electric current converters categories.
Gallium nitride (GaN) technology is being adopted in a variety of power electronic applications due to their high efficiencies even at high switching speeds. In comparison with the silicon (Si) transistors, the GaN-based devices exhibit lower on-state resistance and parasitic capacitances. The thermal performance of the GaN transistors are also better than the Si counterparts due to their higher junction temperature and lower temperature-coefficient of on-resistance. These unique properties make the gallium-nitride power transistors an appropriate selection for power electronic converters and radio-frequency power amplifiers, where size, efficiency, power density, and dynamic performance are major requirements. Foreseeing the immense capabilities of the GaN transistors in the near future for the fast-growing electronic industry, this thesis endeavors to make the following contributions: (a) analyze the important properties of GaN as a semiconductor material, (b) study the formation of the 2-dimensional electron gas layer required for current conduction, (c) determine the functionality of the GaN as a field-effect transistor, and (d) test its performance through simulations and experiments at high switching frequencies in power electronic converters, where the Si-based transistors cease to operate normally. The critical material properties include the intrinsic carrier concentration, the specific on-resistance, and the intrinsic carrier mobility. The dependence of these properties on the temperature is investigated. The comparison of these properties are made with the silicon and silicon-carbide (SiC) semiconductor materials to give a clear view about the superior performance of GaN over the other types. While the Si MOSFETs create a channel to conduct the electrons and holes between the source and drain terminals, the GaN field-effect transistors (FET) form a 2-dimensional electron gas (2-DEG) layer, whose thickness is controlled by the applied gate potential. Because of the high electron density in the 2-DEG layer, the GaN FETs are termed as high-electron mobility transistors (HEMT). The operation of both enhancement and depletion mode GaN FETs are discussed in detail and the model of the drain current through the 2-DEG layer is provided. The figure-of-merit (FOM) for the GaN transistors is explained and then compared with that of Si and SiC transistors. Two important implementations of GaN transistors are in the (a) pulse-width modulated synchronous-buck DC-DC power converters and (b) Class-D resonant inverters. These circuits are better representative examples since they comprise of one GaN FET (high-side switch) connected to a "hot" point and the other GaN FET (low-side switch) referenced to ground. While the low-side switch consumes minimum gate-drive power for turn ON/OFF transitions, the high-side switch demands a higher gate-drive power to operate the transistor as a switch. Also, these switches exhibit switching losses due to the charge/discharge process of the parasitic capacitances. The gate-drive power and switching losses increase as the switching frequency is increased. However, due to the superior performance and very low values of the device parasitic resistances and capacitances in the GaN transistors, higher switching frequencies can be achieved at very minimal switching losses. Simulations were performed to analyze the behavior of the two circuits at different switching frequencies and were compared with those using Si transistors. It is observed that the overall efficiency reduced to 48% at 5 MHz for the Si-based buck converter and down to 41% at 5 MHz for the Si-based Class-D inverter. However, using GaN transistors showed an improved performance, where the overall efficiency reduced to only 71% at 15 MHz for the buck converter and 60% at 10 MHz for the Class-D inverter. Further, experimental validations were performed on a prototype of the synchronous buck converter developed using the high-frequency, half-bridge switching network module EPC9037 manufactured by Efficient Power Conversion Corporation. The module comprises of the enhancement-mode GaN transistors and a high-speed, dual-side, high-performance gate-driver LM5113 by Texas Instruments. The experimental results showed the immense capability of the GaN transistors to achieve high efficiencies. The experimentally measured efficiency of the synchronous buck converter was 85% at a switching frequency of 5 MHz and reduced to 60% at 8MHz. The theoretical predictions were in good agreement with simulation and experiment results.