Download or read book Development of High Temperature High Power High Efficiency High Voltage Converters Using Silicon Carbide SiC Delivery Order Delivery Order 0002 Critical Analysis of SiC VJFET Design and Performance Based Upon Material and Device Properties written by and published by . This book was released on 2005 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Silicon carbide as a semiconductor material possesses several significant physical properties which make it superior for applications to high power devices. This report documents the efforts to develop, demonstrate, and optimize the design and fabrication methodologies for the realization of power vertical junction field effect transistors in the 4H-polytype of silicon carbide. Theoretical prediction and modeling simulation, incorporating all the significant SiC specific device physics, are utilized to develop a design methodology which is to ultimately be used for device fabrication. The results illustrate that good agreement between theoretical prediction and accurately modeled simulations can be achieved and enable the forecasting of device performance as a function of temperature, design modification, and variations in material transport characteristics.
Download or read book High Efficiency Silicon Carbide SiC Converters Delivery Order 0001 Development of High Temperature High Power High Efficiency High Voltage Converters Using Silicon Carbide written by and published by . This book was released on 2004 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: A design based on a self- aligned, gate-implanted, trenched source-gate junction FET was selected for its near term technological readiness and its long term manufacturability. This project concentrated on several key processes required for the realization of a viable VJFET fabrication technology, namely, 1) Development of silicon carbide dry (plasma) etches; 2) Development of appropriate edge termination technology; and 3) Development of implantation and annealing recipes core to the design. Semiconductor devices, principally the Schottky barrier diode and the PiN junction rectifier, were fabricated to test design assumptions and to evaluate new process steps. The principal accomplishments of the effort can be summarized as follows: 1) The completion of a design for a 600-V self-aligned, gate-implanted, trench VJFET, shown to deliver blocking voltages in excess of 800 V, an specific on resistance as low as 5 mohm-cm2; 2) The development of critical VJFET and rectifier device fabrication processes, and 3) The demonstration of a multi-wafer PiN diode lot of 1.5 kV PiN diodes.
Download or read book Development of High Temperature High Power High Efficiency High Voltage Converters Using Silicon Carbide SiC Delivery Order 0003 SiC High Voltage Converters N Type Ohmic Contract Development for SiC Power Devices written by and published by . This book was released on 2006 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The durability and reliability of metal-semiconductor contacts are two of the main factors limiting the operational high-temperature limits of SiC electronic devices. To date, nickel (Ni) has been the most widely used metal for ohmic contacts to n-type SiC. The way to make smooth Ni-silicide? SiC interfaces and silicide top surfaces is important for producing uniformly low contact resistances to achieve device operation at high-current levels without hot spot formation and contact degradation. For as-deposited single Ni thin layers, agglomeration of Ni-silicide after annealing can happen depending on the conditions of deposition and thermal annealing processes. This is mainly due to the residual stress on the Ni films after deposition on SiC with a significantly lower coefficient of thermal expansion. Typically, an additional stress reduction layer, such as titanium, is deposition on top of the Ni thin contact film to prevent silicide agglomeration. The objective of this Delivery Order Task was to study and develop a process to produce robust, smooth ohmic contact, with low contact resistivity, to n-type SiC for high power, high temperature, and harsh radiation environments.
Download or read book CVD growth of SiC for high power and high frequency applications written by Robin Karhu and published by Linköping University Electronic Press. This book was released on 2019-02-14 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Silicon Carbide (SiC) is a wide bandgap semiconductor that has attracted a lot of interest for electronic applications due to its high thermal conductivity, high saturation electron drift velocity and high critical electric field strength. In recent years commercial SiC devices have started to make their way into high and medium voltage applications. Despite the advancements in SiC growth over the years, several issues remain. One of these issues is that the bulk grown SiC wafers are not suitable for electronic applications due to the high background doping and high density of basal plane dislocations (BPD). Due to these problems SiC for electronic devices must be grown by homoepitaxy. The epitaxial growth is performed in chemical vapor deposition (CVD) reactors. In this work, growth has been performed in a horizontal hot-wall CVD (HWCVD) reactor. In these reactors it is possible to produce high-quality SiC epitaxial layers within a wide range of doping, both n- and p-type. SiC is a well-known example of polytypism, where the different polytypes exist as different stacking sequences of the Si-C bilayers. Polytypism makes polytype stability a problem during growth of SiC. To maintain polytype stability during homoepitaxy of the hexagonal polytypes the substrates are usually cut so that the angle between the surface normal and the c-axis is a few degrees, typically 4 or 8°. The off-cut creates a high density of micro-steps at the surface. These steps allow for the replication of the substrates polytype into the growing epitaxial layer, the growth will take place in a step-flow manner. However, there are some drawbacks with step-flow growth. One is that BPDs can replicate from the substrate into the epitaxial layer. Another problem is that 4H-SiC is often used as a substrate for growth of GaN epitaxial layers. The epitaxial growth of GaN has been developed on on-axis substrates (surface normal coincides with c-axis), so epitaxial 4H-SiC layers grown on off-axis substrates cannot be used as substrates for GaN epitaxial growth. In efforts to solve the problems with off-axis homoepitaxy of 4H-SiC, on-axis homoepitaxy has been developed. In this work, further development of wafer-scale on-axis homoepitaxy has been made. This development has been made on a Si-face of 4H-SiC substrates. The advances include highly resistive epilayers grown on on-axis substrates. In this thesis the ability to control the surface morphology of epitaxial layers grown on on-axis homoepitaxy is demonstrated. This work also includes growth of isotopically enriched 4H-SiC on on-axis substrates, this has been done to increase the thermal conductivity of the grown epitaxial layers. In (paper 1) on-axis homoepitaxy of 4H-SiC has been developed on 100 mm diameter substrates. This paper also contains comparisons between different precursors. In (paper 2) we have further developed on-axis homoepitaxy on 100 mm diameter wafers, by doping the epitaxial layers with vanadium. The vanadium doping of the epitaxial layers makes the layers highly resistive and thus suitable to use as a substrate for III-nitride growth. In (paper 3) we developed a method to control the surface morphology and reduce the as-grown surface roughness in samples grown on on-axis substrates. In (paper 4) we have increased the thermal conductivity of 4H-SiC epitaxial layers by growing the layers using isotopically enriched precursors. In (paper 5) we have investigated the role chlorine have in homoepitaxial growth of 4H-SiC. In (paper 6) we have investigated the charge carrier lifetime in as-grown samples and traced variations in lifetime to structural defects in the substrate. In (paper 7) we have investigated the formation mechanism of a morphological defect in homoepitaxial grown 4H-SiC.
Download or read book Design Characterization Modeling and Analysis of High Voltage Silicon Carbide Power Devices written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This research focuses on the design, characterization, modeling and analysis of high voltage Silicon Carbide (SiC) metal-oxide-semiconductor field effect transistors (MOSFET), insulated gate bipolar transistors (IGBT) and emitter turn-off thyristors (ETO) to satisfy the stringent requirements of advanced power electronic systems. The loss information, frequency capability and switching ruggedness of these 10-kV SiC power devices are studied extensively in order to provide their application prospects in solid-state transformers (SST). Among 10-kV SiC power devices, SiC MOSFETs are of the greatest interest due to their lower specific on-resistance compared to silicon MOSFETs, and their inherently fast switching speed due to their majority carrier conduction mechanism. Therefore, 10-kV SiC MOSFETs are studied first in this dissertation. The characterization, modeling and analysis of 10-kV SiC MOSFETs were investigated extensively. The low losses and high switching frequency of 10-kV SiC MOSFETs were demonstrated in characterization study and a 4-kV 4 kW boost converter. The on-resistance of SiC MOSFETs increases rapidly with increased junction temperature and blocking voltage. This makes their conduction losses possibly unacceptable for applications where high DC supply voltages (more than 10-kV) and high temperature operation are used. This warrants the development of SiC bipolar devices (IGBTs and thyristors) to achieve smaller conduction losses due to the conductivity modulation of their thick drift layers, especially at elevated temperatures. Therefore, design, characterization and optimization of 10-kV SiC IGBT and ETO were dicussed. A 4H-SiC p-channel IGBT with improved conduction characteristics was developed and characterized experimentally as well as analyzed theoretically by numerical simulations. The device exhibited a differential on-resistance of 26 mOhm.cm^2 at a collector current density of 100 A/cm^2 at room temperature. An the SiC IGBT showed a turn-of.
Download or read book Characterization and Realization of High Switching speed Capability of SiC Power Devices in Voltage Source Converter written by Zheyu Zhang and published by . This book was released on 2015 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: The emerging wide band-gap, silicon carbide (SiC) power devices greatly improve the switching performance due to their inherent fast switching capability. However, the high switching-speed performance makes their switching behavior become more susceptible to parasitics of the application circuit. In the end, unlike the excellent switching performance of SiC devices tested in manufacturer' datasheets, the observed switching performance in actual power converters is almost always worse. This dissertation aims at characterization and realization of high switching-speed capability of SiC devices in one of the most widely used converter types, the voltage source converter (VSC). To evaluate the fast dynamic characteristics of SiC devices with high fidelity, a methodology of switching performance characterization is summarized. The assessed switching loss is highly sensitive to V−I timing alignment and cross-talk. A practical method is proposed to cope with these issues for accurate switching loss evaluation. Based on the methodology of switching performance characterization, limitations and impact factors of switching performance of SiC devices in VSC are explored. Cross-talk, turn-on overvoltage, and parasitics of inductive loads are identified as the "killer" impact factors. To suppress cross-talk, intelligent gate drivers are designed to be capable of tuning the gate voltage and gate resistance during different switching transients for both devices in a phase-leg. The spurious gate voltage induced by cross-talk can be limited, leading to the improved switching performance with fast switching speed and low switching losses. To mitigate the turn-on over-voltage and parasitic ringing, the placement of gate drivers, devices and power stage and layout design for SiC devices with TO package are proposed and implemented, enabling 30% power loop and common source inductance reduction. To decouple the interaction between devices and inductive load, a dedicated auxiliary filter is introduced to reshape the inductive load's high frequency impedance, allowing the switching behavior to become as excellent as that tested by the optimally-designed inductor. In the end, a SiC based three-phase VSC fed motor drives are built by using the knowledge and techniques developed above. It shows that switching behaviors in VSC have nearly identical performance as that characterized in the optimally-designed switching test circuit.
Download or read book SiC Materials and Devices written by Michael Shur and published by World Scientific. This book was released on 2007 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: Silicon carbide is known to have been investigated since 1907 when Captain H J Round demonstrated yellow and blue emission by applying bias between a metal needle and an SiC crystal. The potential of using SiC in semiconductor electronics was already recognized half a century ago. Despite its well-known properties, it has taken a few decades to overcome the exceptional technological difficulties of getting silicon carbide material to reach device quality and travel the road from basic research to commercialization. This second of two volumes reviews four important additional areas: the growth of SiC substrates; the deep defects in different SiC polytypes, which after many years of research still define the properties of bulk SiC and the performance and reliability of SiC devices; recent work on SiC JFETs; and the complex and controversial issues important for bipolar devices. Recognized leaders in the field, the contributors to this volume provide up-to-date reviews of further state-of-the-art areas in SiC technology and materials and device research.
Download or read book Enabling High Efficiency Medium Voltage Converter for High Speed Drives and Other Grid Applications Using Low Voltage LV and High Voltage HV Silicon Carbide SiC Devices written by Kasunaidu Vechalapu and published by . This book was released on 2018 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Power Packaging of Spray Cooled SiC Devices for High Temperature and High Voltage Operation Final Report written by and published by . This book was released on 2008 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: Main objective was developing the foundation for designing sprayed cooled power packages for semiconductors like silicon-carbide devices capable of high temperature and voltage operation. Research addressed: (1) Understanding of the heat transfer phenomenon during spray cooling under phase change; (2) Packaging materials for high temperature and spray cooling or jet impingement; (3) A scaled down spray-cooled power package of a power conversion module; and (4) New electric topologies of power conversion modules for integration with spray-cooling solutions. Main conclusions were: (1) Quick replacement of hot liquid by cold liquid (i.e., transient conduction) is main mechanism enabling high heat fluxes; (2) Jet impingement without nozzles provides cost effective solutions; (3) Several high temperature active metal brazing materials suitable for high temperature die attach but requiring more research to ensure proper chemical behavior; (4) A double-sided power package providing minimized volumetric footprint for the spray box and integrates the power electronic systems; and (5) Several new electric topologies of power conversion modules.
Download or read book 4H SiC Integrated Circuits for High Temperature and Harsh Environment Applications written by Mihaela Alexandru and published by . This book was released on 2014 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Silicon Carbide (SiC) has received a special attention in the last decades thanks to its superior electrical, mechanical and chemical proprieties. SiC is mostly used for applications where Silicon is limited, becoming a proper material for both unipolar and bipolar power device able to work under high power, high frequency and high temperature conditions. Aside from the outstanding theoretical and practical advantages still to be proved in SiC devices, the need for more accurate models for the design and optimization of these devices, along with the development of integrated circuits (ICs) on SiC is indispensable for the further success of modern power electronics. The design and development of SiC ICs has become a necessity since the high temperature operation of ICs is expected to enable important improvements in aerospace, automotive, energy production and other industrial systems. Due to the last impressive progresses in the manufacturing of high quality SiC substrates, the possibility of developing ICs applications is now feasible. SiC unipolar transistors, such as JFETs and MESFETs show a promising potential for digital ICs operating at high temperature and in harsh environments. The reported ICs on SiC have been realized so far with either a small number of elements, or with a low integration density. Therefore, this work demonstrates that by means of our SiC MESFET technology, multi-stage digital ICs fabrication containing a large number of 4H-SiC devices is feasible, accomplishing some of the most important ICs requirements. The ultimate objective is the development of SiC digital building blocks by transferring the Si CMOS topologies, hence demonstrating that the ICs SiC technology can be an important competitor of the Si ICs technology especially in application fields in which high temperature, high switching speed and harsh environment operations are required. The study starts with the current normally-on SiC MESFET CNM complete analysis of an already fabricated MESFET. It continues with the modeling and fabrication of a new planar-MESFET structure together with new epitaxial resistors specially suited for high temperature and high integration density. A novel device isolation technique never used on SiC before is approached. A fabrication process flow with three metal levels fully compatible with the CMOS technology is defined. An exhaustive experimental characterization at room and high temperature (300oC) and Spice parameter extractions for both structures are performed. In order to design digital ICs on SiC with the previously developed devices, the current available topologies for normally-on transistors are discussed. The circuits design using Spice modeling, the process technology, the fabrication and the testing of the 4H-SiC MESFET elementary logic gates library at high temperature and high frequencies are performed. The MESFET logic gates behavior up to 300oC is analyzed. Finally, this library has allowed us implementing complex multi-stage logic circuits with three metal levels and a process flow fully compatible with a CMOS technology. This study demonstrates that the development of important SiC digital blocks by transferring CMOS topologies (such as Master Slave Data Flip-Flop and Data-Reset Flip-Flop) is successfully achieved. Hence, demonstrating that our 4H-SiC MESFET technology enables the fabrication of mixed signal ICs capable to operate at high temperature (300oC) and high frequencies (300kHz). We consider this study an important step ahead regarding the future ICs developments on SiC. Finally, experimental irradiations were performed on W-Schotthy diodes and mesa-MESFET devices (with the same Schottky gate than the planar SiC MESFET) in order to study their radiation hardness stability. The good radiation endurance of SiC Schottky-gate devices is proven. It is expected that the new developed devices with the same W-Schottky gate, to have a similar behavior in radiation rich environments.
Download or read book A High temperature High voltage SOI Gate Driver Integrated Circuit with High Drive Current for Silicon Carbide Power Switches written by Mohammad Aminul Huque and published by . This book was released on 2010 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-temperature integrated circuit (IC) design is one of the new frontiers in microelectronics that can significantly improve the performance of the electrical systems in extreme environment applications, including automotive, aerospace, well-logging, geothermal, and nuclear. Power modules (DC-DC converters, inverters, etc.) are key components in these electrical systems. Power-to-volume and power-to-weight ratios of these modules can be significantly improved by employing silicon carbide (SiC) based power switches which are capable of operating at much higher temperature than silicon (Si) and gallium arsenide (GaAs) based conventional devices. For successful realization of such high-temperature power electronic circuits, associated control electronics also need to perform at high temperature. In any power converter, gate driver circuit performs as the interface between a low-power microcontroller and the semiconductor power switches. This dissertation presents design, implementation, and measurement results of a silicon-on-insulator (SOI) based high-temperature (>200° C) and high-voltage (>30 V) universal gate driver integrated circuit with high drive current (>3 A) for SiC power switches. This mixed signal IC has primarily been designed for automotive applications where the under-hood temperature can reach 200° C. Prototype driver circuits have been designed and implemented in a Bipolar-CMOS- DMOS (BCD) on SOI process and have been successfully tested up to 200° C ambient temperature driving SiC switches (MOSFET and JFET) without any heat sink and thermal management. This circuit can generate 30V peak-to-peak gate drive signal and can source and sink 3A peak drive current. Temperature compensating and temperature independent design techniques are employed to design the critical functional units like dead-time controller and level shifters in the driver circuit. Chip-level layout techniques are employed to enhance the reliability of the circuit at high temperature. High-temperature test boards have been developed to test the prototype ICs. An ultra low power on-chip temperature sensor circuit has also been designed and integrated into the gate-driver die to safeguard the driver circuit against excessive die temperature (> 220° C). This new temperature monitoring approach utilizes a reverse biased p-n junction diode as the temperature sensing element. Power consumption of this sensor circuit is less than 10 [mu]W at 200° C.
Download or read book Modeling And Electrothermal Simulation Of Sic Power Devices Using Silvaco Atlas written by Pushpakaran Bejoy N and published by World Scientific. This book was released on 2019-03-25 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary goal of this book is to provide a sound understanding of wide bandgap Silicon Carbide (SiC) power semiconductor device simulation using Silvaco© ATLAS Technology Computer Aided Design (TCAD) software. Physics-based TCAD modeling of SiC power devices can be extremely challenging due to the wide bandgap of the semiconductor material. The material presented in this book aims to shorten the learning curve required to start successful SiC device simulation by providing a detailed explanation of simulation code and the impact of various modeling and simulation parameters on the simulation results. Non-isothermal simulation to predict heat dissipation and lattice temperature rise in a SiC device structure under switching condition has been explained in detail. Key pointers including runtime error messages, code debugging, implications of using certain models and parameter values, and other factors beneficial to device simulation are provided based on the authors' experience while simulating SiC device structures. This book is useful for students, researchers, and semiconductor professionals working in the area of SiC semiconductor technology. Readers will be provided with the source code of several fully functional simulation programs that illustrate the use of Silvaco© ATLAS to simulate SiC power device structure, as well as supplementary material for download.
Download or read book High Temperature SiC Power Module with Integrated SiC Gate Drivers for Future High Density Power Electronics Applications written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents the testing results of an all-silicon carbide (SiC) intelligent power module (IPM) for use in future high-density power electronics applications. The IPM has high-temperature capability and contains both SiC power devices and SiC gate driver integrated circuits (ICs). The high-temperature capability of the SiC gate driver ICs allows for them to be packaged into the power module and be located physically close to the power devices. This provides a distinct advantage by reducing the gate driver loop inductance, which promotes high frequency operation, while also reducing the overall volume of the system through higher levels of integration. The power module was tested in a bridgeless-boost converter to showcase the performance of the module in a system level application. The converter was initially operated with a switching frequency of 200 kHz with a peak output power of approximately 5 kW. The efficiency of the converter was then evaluated experimentally and optimized by increasing the overdrive voltage on the SiC gate driver ICs. Overall a peak efficiency of 97.7% was measured at 3.0 kW output. The converter s switching frequency was then increased to 500 kHz to prove the high frequency capability of the power module was then pushed to its limits and operated at a switching frequency of 500 kHz. With no further optimization of components, the converter was able to operate under these conditions and showed a peak efficiency of 95.0% at an output power of 2.1 kW.
Download or read book Simulation Modeling and Characterization of SiC Devices written by Liangchun Yu and published by . This book was released on 2010 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: With superior material properties, Silicon carbide (SiC) power devices show great potential for high-power density, high temperature switching applications. Among all the power device structures, SiC MOSFET attracts the most attention because of its high gate input impedance, simple gate control and fast switching speed. However, low inversion channel mobility, high near-interface state density close to the conduction band edge, questionable oxide reliability as well as theoretical limit on the device figure-of-merit still remain to be significant challenges to the development of SiC power MOSFETs. In this dissertation, all of the above challenges are addressed from various approaches. First, simulations on the super-junction structure show that the unipolar theoretical limit of SiC can be broken even with the state-of-the-art processing technologies. An easy-to-implement analytical model is developed for calculations of the blocking voltage, specific on-resistance and charge imbalance effects of 4H-SiC super-junction devices. This model is validated by extensive numerical simulations with a large variety of device parameters. Device design and optimization using this model are also presented. Second, a wafer-level Hall mobility measurement technique is developed to measure channel mobility more accurately, more efficiently and more cost-effectively. Device characterization and development are much more convenient by using this technique. With this method, further explorations of interactions between interface traps and channel carriers as well as device degradation mechanisms become possible. Third, reliability of SiO2 on 4H-SiC is characterized with time dependent dielectric breakdown (TDDB) measurements at various temperatures and electric fields. Lifetime prediction to normal operation conditions suggests that the oxide on SiC has a characteristic lifetime of 10 years at 375° C if the oxide electric field is kept below 4.6 MV/cm. The observed excellent reliability data contradict the widespread belief that the oxide on SiC is intrinsically limited by its physical properties. Detailed discussions are provided to re-examine the arguments leading to the misconception.
Download or read book Critical Analysis of SiC Design and Performance Based Upon Material and Device Propertyies written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, the need for high power, high frequency devices continues to grow with the increase in wireless communication, radar systems, HDTV, digital communication, and other military application of the RF spectrum. Traditionally when higher power is needed, one needs to either combine the output power of multiple devices or use vacuum tubes, which are still uncontested at very high power levels, capable of up to a few hundred kilowatts at 5 GHz [11]. But wide band gap semiconductor devices capable of competing in this application. Moreover, the static induction transistor (SIT) in silicon carbide can provide very high total power at microwave frequency. This is due to the vertical structure of the SIT which consists of a vertical channel that is defined by a mesa with gate electrodes of the Schottky type to control the current between a top side source contact and a drain contact on the backside of the wafer. This thesis demonstrates that through careful modeling by means of simulations and inclusion of all significant device physics, good agreement is reached between theoretical prediction and simulation results. It is shown in particular that by careful choice of the device critical parameters, such as mesa width, gate length, and contact resistance, SIT should be able to obtain cut-off frequency up to 42 GHz and shown temperature simulation results of SIT.
Download or read book Power GaN Devices written by Matteo Meneghini and published by Springer. This book was released on 2016-09-08 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Critical Analysis of SiC SIT Design and Performance Based Upon Material and Device Properties written by YunMo Sung and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, the need for high power, high frequency devices continues to grow with the increase in wireless communication, radar systems, HDTV, digital communication, and other military application of the RF spectrum. Traditionally when higher power is needed, one needs to either combine the output power of multiple devices or use vacuum tubes, which are still uncontested at very high power levels, capable of up to a few hundred kilowatts at 5 GHz [11]. But wide band gap semiconductor devices capable of competing in this application. Moreover, the static induction transistor (SIT) in silicon carbide can provide very high total power at microwave frequency. This is due to the vertical structure of the SIT which consists of a vertical channel that is defined by a mesa with gate electrodes of the Schottky type to control the current between a top side source contact and a drain contact on the backside of the wafer. This thesis demonstrates that through careful modeling by means of simulations and inclusion of all significant device physics, good agreement is reached between theoretical prediction and simulation results. It is shown in particular that by careful choice of the device critical parameters, such as mesa width, gate length, and contact resistance, SIT should be able to obtain cut-off frequency up to 42 GHz and shown temperature simulation results of SIT.
