Silicon Carbide Power Semiconductor Research Articles

Leveraging Silicon Carbide Power Semiconductor Devices for Renewable Energy Applications

Leveraging Silicon Carbide Power Semiconductor Devices for Renewable Energy Applications

The role of power device technology in the electric vehicle powertrain

In the automotive industry, the design and implementation of power converters and especially inverters, are at a turning point. Silicon (Si) IGBTs are at present the most widely used power semiconductors in most commercial vehicles. However, this trend is beginning to change with the appearance of wide-bandgap (WBG) devices, particularly silicon carbide (SiC) and gallium nitride (GaN). It is therefore advisable to review their main features and advantages, to update the degree of their market penetration, and to identify the most commonly used alternatives in automotive inverters. In this paper, the aim is therefore to summarize the most relevant characteristics of power inverters, reviewing and providing a global overview of the most outstanding aspects (packages, semiconductor internal structure, stack-ups, thermal considerations, etc.) of Si, SiC, and GaN power semiconductor technologies, and the degree of their use in electric vehicle powertrains. In addition, the paper also points out the trends that semiconductor technology and next-generation inverters will be likely to follow, especially when future prospects point to the use of “800 V" battery systems and increased switching frequencies. The internal structure and the characteristics of the power modules are disaggregated, highlighting their thermal and electrical characteristics. In addition, aspects relating to reliability are considered, at both the discrete device and power module level, as well as more general issues that involve the entire propulsion system, such as common-mode voltage.

Semiconductor Materials for Solar PV Technology and Challenges towards Electrical Engineering

The contemporary concern in worldwide power scenario and consumption rate is frightening significantly at a marvelous amount of population, and it originates a very high augment in the electrical energy area. The all-embracing attraction and manufacture of fossil energy is the chief reason in the ecological issues. Due to these relic fuels, the ecological resources get exhausted, and it results in climatic change. Due to these negative aspects, every country puts effort to bring the energy efficiency high with the help of renewable energy. Presently, the solar energy donation worldwide decreases. Contrarily, solar energy contribution to the global energy is highly contrary to nonconventional energy resources. But there is a progress in power generation, and it plays a vital role in solar photovoltaic generation. Gallium nitride and silicon carbide power semiconductors will emerge to bring the efficiency high in the photovoltaic technology. In this work, we will converse about how to increase the efficiency by using gallium nitride.

Production of silicon carbide power semiconductor devices in Russia - challenges and opportunities

Production of silicon carbide power semiconductor devices in Russia - challenges and opportunities

Systematic Characterization of Plasma-Etched Trenches on 4H-SiC Wafers.

Silicon carbide power semiconductors overcome some limitations of silicon chips, and therefore, SiC is an attractive candidate for next-generation power electronics. In addition, the number of possible vertical devices that can be obtained on a given surface using the trench technique is significantly larger than that attainable using a planar setup. Moreover, a SiC trench power metal oxide semiconductor field-effect transistor (power MOSFET) structure removes the junction field-effect transistor (JFET) region (that would decrease the current flow width) and improves the channel density, thus reducing the specific electrical resistance. Consequently, in the present study, we report on the chemical bonding state of elements and structural characterization of trenches, obtained using SF6-based plasma etching, on the 4H-SiC polytype substrate. An interferometric algorithm that finds the endpoint to stop etching governed the trench depth. Scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy analyses stated the high quality and uniformity of the trenches. These materials are particularly promising for the fabrication of the SiC MOSFET to be implemented in the manufacturing of power devices.

Benefits of high-voltage SiC-based power electronics in medium-voltage power-distribution grids

Medium-voltage (MV) power electronics equipment has been increasingly applied in distribution grids, and high-voltage (HV) silicon carbide (SiC) power semiconductors have attracted considerable attention in recent years. This paper first overviews the development and status of HV SiC power semiconductors. Then, MV power-converter applications in distribution grids are summarized and the benefits of HV SiC in these applications are presented. Microgrids, including conventional and asynchronous microgrids, that can fully demonstrate the benefits of HV SiC power semiconductors are selected to investigate the benefits of HV SiC in detail, including converter-level benefits and system-level benefits. Finally, an asynchronous microgrid power-conditioning system (PCS) prototype using a 10 kV SiC MOSFET is presented.

Comparative Evaluation of Voltage Source Converters With Silicon Carbide Semiconductor Devices for High-Voltage Direct Current Transmission

Recent advancements in silicon carbide (SiC) power semiconductor technology enable developments in the high-power sector, e.g., high-voltage-direct-current (HVdc) converters for transmission, where today silicon (Si) devices are state-of-the-art. New submodule (SM) topologies for modular multilevel converters offer benefits in combination with these new SiC semiconductors. This article reviews developments in both fields, SiC power semiconductor devices and SM topologies, and evaluates their combined performance in relation to core requirements for HVdc converters: grid code compliance, reliability, and cost. A detailed comparison of SM topologies regarding their structural properties, design and control complexity, voltage capability, losses, and fault handling is given. Alternatives to state-of-the-art SMs with Si insulated-gate bipolar transistors (IGBTs) are proposed, and several promising design approaches are discussed. Most advantages can be gained from three technology features. First, SM bipolar capability enables dc fault handling and reduced the energy storage requirements. Second, SM topologies with parallel conduction paths in combination with SiC metal-oxide-semiconductor field-effect transistors offer reduced losses. Third, a higher SM voltage enabled by a higher blocking voltage of SiC devices results in a reduced converter complexity. For the latter, ultrahigh-voltage bipolar devices, such as SiC IGBTs and SiC gate turn-off thyristors, are envisioned.

Comparative Performance and Assessment Study of a Current-Fed DC-DC Resonant Converter Combining Si, SiC, and GaN-Based Power Semiconductor Devices

This paper focuses on the main reasons of low efficiency in a current-fed DC-DC resonant converter applied to photovoltaic (PV) isolated systems, comparing the effects derived by the overlapping time in the gate-signals (gate-source voltage) combining silicon (Si), silicon carbide (SiC), and gallium nitride (GaN)-based power devices. The results show that unidirectional switches (metal–oxide–semiconductor field-effect transistors (MOSFETs) plus diode) present hard switching as a result of the diode preventing the MOSFET capacitance of being discharged. The effectiveness of the converter was verified with a 200-W prototype with an input voltage range of 0–30.3 V, an output voltage of 200 V, and a switching frequency of 200 kHz. The reduction losses by applying GaN versus Si and SiC technologies are 66.49% and 53.57%, respectively. Alternatively, by applying SiC versus Si devices the reduction loss is 27.84%. Finally, according to the results, 60% of losses were caused by the diodes on both switches.

Development of a World Class Silicon Carbide Substrate Manufacturing Capability

Silicon carbide (SiC) semiconductor substrates provide the foundation for revolutionary improvements in the cost, size, weight and performance of a broad range of military and commercial radio frequency (RF) and power switching devices. Due to the lack of a viable, native gallium nitride (GaN) substrate, semi-insulating (SI) SiC substrates are the substrate of choice for high power AlGaN/GaN High Electron Mobility Transistors (HEMTs) due to their near lattice-match to GaN, superior thermal conductivity and commercial availability. GaN has emerged as the technology of choice for RF power because of its superior output power capability compared to other semiconductors. Similarly, semi-conducting (N+) SiC substrates are required for fabrication of high voltage Schottky Diodes and Metal Oxide Semiconductor Field Effect Transistor (MOSFET) power switching devices. Critical to this realization is the availability of affordable, high quality, large diameter SI and N+ SiC substrates for production of GaN and SiC power semiconductors. SiC is unique in that bulk single crystals cannot be grown via traditional melt-based manufacturing processes such as Czochralski. Rather, a high temperature sublimation process is required. In the late 1980’s, pioneering physical vapor transport research taking place at North Carolina State University ultimately led to the formation of Cree Research and subsequently the wide bandgap semiconductor industry. U.S. Department of Defense investment in wide bandgap semiconductor development has easily exceeded $1B spawning the creation of an entirely new industry. During the early 1990’s, SiC physical vapor transport growth development was fraught with perceived insurmountable technical challenges associated with micropipes, polytype conversion, diameter expansion and crystalline defects. Despite these monumental crystal growth technology hurdles, SiC substrates are now manufactured at a cost and quality never thought possible. This article highlights more than 20 years of Air Force Research Laboratory (AFRL) sponsored development with II-VI aimed at positioning itself as a merchant, world-class manufacturer of SiC substrates.

MV Power Conversion Systems Enabled by High-Voltage SiC Devices [Happenings

Reports on medium voltage (MV0 power conversion systems that are enabled by high-voltage silicon carbide (SiC) devices. Thanks to recent strides in power electronics research and the availability of high-voltage SiC power semiconductor devices, we can contemplate building a smart “solid-state transformer” to handle the demands of the smart grid. In electrical distribution systems, the transformers convert thousands of volts MV into lower voltages that can be safely used in homes and businesses. With emerging technologies in building and fabricating MV SiC-based power semiconductor devices, MV power conversion on a large-scale scenario seems feasible. While companies, such as Wolfspeed (CREE), General Electric, Infineon Technologies, Mitsubishi, and ROHM, continue to develop and improve these MV semiconductor devices, we at the FREEDM Systems Center are aiming at the application side of things to ensure a market for these power devices.

(Invited) Emerging Role of Silicon Carbide and Gallium Nitride Based Power Electronics in Power and Transportation Sectors

Free fuel-based energy sources (solar and wind) are demonstrating three long term trends in the electrification of sustainable energy. The three trends point toward a future in which sustainable energy is affordable, abundant and deployed with high energy efficiency. These three trends are going to have major economic, geo-political and environmental benefits to humanity. Driven by advancements in the technology of lithium batteries (cost reduction and increase in energy density), and the availability of low-cost sustainable clean electric power, the electrification of surface and air transportation is going through fundamental disruptive transformation. Volume manufacturing, similar to photovoltaic modules is mainly responsible for the cost reduction of lithium ion batteries. Doubling the volume of cumulative manufacturing leads to a cost reduction of about 22% in lithium ion batteries. Similar to Tesla’s Gigawatt factory in the United States, a number of manufacturers in China, Japan and South Korea are setting up ultra-large-scale manufacturing of lithium ion batteries. The long-term cost of supplying grid electricity from today’s lithium-ion batteries is falling even faster than expected, making them an increasingly cost-competitive alternative to natural-gas-fired power plants across a number of key energy markets. As an example, on March 28, 2019 Florida Power and Light in the United States announced that it would retire two natural gas plants and replace those plants with what is likely to be world’s largest photovoltaics-powered battery bank when it’s completed in 2021. Thus, without any doubt, both power and transportation sectors will provide phenomenal growth of power electronics in the 21st century. What role the silicon Carbide (SiC) and gallium nitride (GaN) based power electronics will play in the power and transportation sectors? The importance of SiC based power devices has been realized almost at the same time when silicon based low power devices were being developed in 50s. In the 21st century both SiC and GaN are drawing the attention as potential replacement of Si based power electronics and may open some new markets where Si based power electronics cannot function either due to power or temperature limitations. Public private funding agencies such as United States of Department of Energy have addressed the challenges and opportunities of wide band gap semiconductor power electronics [1]. According to a report from IHS market, the emerging market for SiC and GaN power semiconductors is expected to reach nearly $1 billion in 2020 [2]. While it is true that there exists a niche market GaN products, the phenomenal growth of WBG power electronics is questionable. To compare the cost of Si and GaN based products, we have plotted the cost of Si and GaN MOSFET’s as a function of volume of purchased devices in Figure [3, 4]. For 250 units (highest volume price listed in reference 4), the cost compared to a single GaN transistor has been reduced by 13.8 %. On the other hand, for 250 units, the cost of a single Si transistor is reduced by 35.6 %. Thus, cost is the major barrier in replacing Si based power electronics by WBG based power electronics. In an earlier publication [5], we have discussed the pathways that can lead to the reduction of manufacturing cost of WBG based products. Photovoltaics generates direct current (DC) power and batteries store DC power. As compared to alternating current power, at least 30 % capital cost and the cost of electric power is saved by local DC power networks. Direct current (DC) power enables fast charging of electric vehicles. Thus, the use of low voltage (<1,500 V) local DC power networks will further reduce the need of inverters but will need DC-DC converters. In this paper we will identify the WBG based key power electronics products that should be focused to see high growth of WBG based power electronics. Cost and performance of 48 V induction cooking device based on Si and GaN MOSFET switches will also be presented. References I. C. Kizilyalli, E. P. Carlson, D. W. Cunningham, J. S. Manser, Y. Xu, A. Y. Liu, March 13, 2018. Available at: https://arpae.energy.gov/sites/default/files/documents/files/ARPA-E_Power_Electronics_Paper-April2018.pdf .R. Aden, April 24, 2018. Available at: https://technology.ihs.com/602187/market-for-gan-and-sic-power-semiconductors-to-top-10-billion-in-2027Available at: https://lcsc.com/product-detail/MOSFET_International-Rectifier_IRFP260MPBF_International-Rectifier-IR-IRFP260MPBF_C2679.htmlAvailable at: https://www.mouser.com/ProductDetail/GaN-Systems/GS66508B-E01-MR?qs=etoTMWSvtH88Sj8NJfVvjg%3D%3D&gclid=EAIaIQobChMI1eHK4_O74QIVEYTICh2L3wLREAAYASAAEgKAzfD_BwER. Singh and A.A. Asif, ECS Transactions, 75(12), 11-18, 2016. Figure 1

Power Electronic Converters and Systems: Frontiers and Applications [Book News

Future power electronics will be dependent on recent silicon carbide power semiconductor devices like SiC metal oxide field effect transistor (MOSFET), SiC insulated gate bipolar transistor (IGBT), and SiC junction field effect transistor (JFET), capable of up to 15 kV hold-off voltages. Compared to silicon (Si), SiC-based power-switching devices present much lower leakage currents, higher blocking voltages, higher operating temperatures, lower on-state voltage drops, higher switching frequency, and higher thermal conductivity. These advanced semiconductor devices integrated within smart power electronic modules can be used to build advanced power converters such as multi-input, multiport converters; modular multilevel cascaded converters (MMCCs); and matrix, Z-source, and Y-source converters. Up-to-date electronic power conversion is priceless for applications like permanent magnet synchronous motor (PMSM) drives, induction motor (IM) drives, renewable energy systems (wind, photovoltaic), energy storage, fuel cells, and electrical vehicles (EV). Power electronic conversion is also the core of modern shipboard power systems, more electric aircrafts, flexible ac power transmission systems, distributed generation (DG) and microgrids, uninterruptible power supplies (UPS), and wireless power transfer (WPT). Assuming the reader is already familiar with the fundamentals of power semiconductors1], electronic power converters, and their control, this book explores and suggests new trends and frontiers in the interdisciplinary field of power electronics systems (PES). In includes contributions from an international panel of 44 PES experts covering subjects such as SiC devices, multilevel and matrix converters (MC), smart power electronic modules, zero voltage switching (ZVS) and zero current switching (ZCS), switching power supplies, EVs, sliding mode and intelligent direct torque control (DTC) of IM drives, sliding mode observers, and model-based predictive control (MPC) of PMSM drives and wind turbines (WTs). The book is also matchless in performing detailed study of contactless power (WPT) and in sequence-based control (SBC) together with the implementation of high-frequency solid-state power transformer (SST) using three-level neutral point clamped multilevel converters built with 15 kV SiC IGBTs. The book is divided in two parts and 20 chapters. It includes preface, table of contents, index, and references at the end of each chapter.

Selective preparation of oligomeric naphthylene ether and its applications to epoxy resin for silicon carbide power semiconductor device materials

ABSTRACTIn this study, a novel method for selective synthesis of naphthylene ether trimers by self‐condensation of 2,7‐dihydroxynaphthalene in the presence of catalytic amount of potassium hydroxide was reported. An epoxy resin from the trimers was prepared and properties of the cured epoxy resin were examined. The cured resin showed not only good physical thermal stability, such as high glass transition temperature and low thermal expansion coefficient, but also good chemical thermal stability like high thermal decomposition temperature. Additionally, low moisture absorption of the cured resin was confirmed. From these results, the newly prepared epoxy resin with naphthylene ether skeletons was considered to be suitable for advanced applications such as silicon carbide power semiconductor device. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43339.

Performance and Reliability of SiC dies, Die attach and Substrates for High Temperature Power Applications up to 300°C

The recent commercial availability of silicon carbide power semiconductor devices are theoretically capable of operating at temperatures well beyond the limits of silicon devices and have generated an interest in developing high temperature capable packaging solutions to match. In this work, the performance and reliability of a number of commercially available silicon carbide power MOSFET dies from multiple vendors was determined for die temperatures up to 350°C. Although these results have demonstrated a number of aging effects and very high on-state resistances at high temperatures, it appears that these devices can perform reliably even in air atmospheres for 100 hours or more at 350°C. In addition, commercially available DBC type ceramic-based substrates have been evaluated for their thermal cycling performance and candidate high temperature capable die attach materials including silver sinter paste and tin and gold-tin pre-form based transient liquid phase types have also been evaluated. These results have demonstrated that the active metal brazed substrates, both copper and aluminium variants, in conjunction with the silicon carbide dies and silver sinter die attach may serve as the basis for high temperature power modules, and may be operated reliably in thermal cycled applications and in air atmospheres up to 300°C. Due to large threshold voltage shift of the SiC MOSFETs at these temperatures, it may be necessary to implement a negative gate bias capability. This work has been carried out under the Innovate UK supported project HITEC, led by Prodrive and also including The University of Warwick, GE Aviation Systems, Ricardo, TT Electronics Semelab, Diamond Hard Surfaces and GaN Systems.

High-Temperature Characterization and Comparison of 1.2 kV SiC Power Semiconductor Devices

Focused on high-temperature (200°C) operation, this paper seeks to provide insight into state-of-the-art 1.2 kV silicon carbide (SiC) power semiconductor devices; namely the MOSFET, BJT, SJT, and normally-off JFET. This is accomplished by characterizing and comparing the latest generation of these wide bandgap devices from various manufacturers (Cree, GE, ROHM, Fairchild, GeneSiC, and SemiSouth). To carry out this study, the static and dynamic characterization of each device is performed under increasing temperatures (25–200°C). Accordingly, this paper describes the experimental setup used and the different measurements conducted, which include: threshold voltage, current gain, specific on-resistance, and the turn-on and turn-off switching energies of the devices. The driving method used for each device is also detailed. Key trends and observations are reported in an unbiased manner throughout the paper and summarized in the conclusion.

High-Temperature Characterization and Comparison of 1.2 kV SiC Power Semiconductor Devices

Focused on high-temperature (200 °C) operation, this paper seeks to provide insight into state-of-the-art 1.2 kV Silicon Carbide (SiC) power semiconductor devices; namely the MOSFET, BJT, SJT, and normally-off JFET. This is accomplished by characterizing and comparing the latest generation of these wide bandgap devices from various manufacturers (Cree, GE, Rohm, Fairchild, GeneSiC, and SemiSouth). To carry out this study, the static and dynamic characterization of each device is performed under increasing temperatures (25–200 °C). Accordingly, this paper describes the experimental setup used and the different measurements conducted, which include: threshold voltage, current gain, specific on-resistance, and the turn-on and turn-off switching energies of the devices. The driving method used for each device is also detailed. Key trends and observations are reported in an unbiased manner throughout the paper and summarized in the conclusion.

Comparison of Si and SiC Power Semiconductor Devices in Power Electronics Converters to be Used in Plug-In Hybrid Electric Vehicles

With the fast development of silicon carbide (SiC) technology, SiC-based power semiconductor is ready to overtake Si in transportation applications. In this paper, Si and SiC-based power electronics converters for plug-in hybrid electric vehicle (PHEV) applications are designed and analyzed. Conduction and switching losses, efficiency, junction temperature, and the volume and weight of heat sinks of converters are calculated for a Si and SiC solution of a 65 kW three-phase inverter and of a 2.5 kW DC/DC converter. Comparison of the parameters mentioned above gives that SiC-based technology shows better performances than Si power semiconductor devices in the investigated converters. Finally, an economical evaluation shows that the SiC components can cost almost 2.5 times more in order to have the same total cost as for a Si solution for a 15 years operation.

Research of Solar Inverter Based on Silicon Carbide JFET Power Device

This paper presents the research of a high frequency, high efficiency Solar inverter using silicon carbide power semiconductor device. Compared to silicon power devices, the silicon carbide power device is more suitable for solar power inverter due to its good electric characteristics. This paper presents the design of sic power semiconductor device based solar inverter. The experiment results of a 1kW silicon carbide JFET based inverter showed about 3% efficiency improvement by a silicon carbide JFET-based inverter over silicon IGBT based inverter.

Z-Source Inverter with SiC Power Semiconductor Devices for Fuel Cell Vehicle Applications

Power electronics is a key technology for electric, hybrid, plug-in hybrid, and fuel cell vehicles. Typical power electronics converters used in electric drive vehicles include dc/dc converters, inverters, and battery chargers. New semiconductor materials such as silicon carbide (SiC) and novel topologies such as the Z-source inverter (ZSI) have a great deal of potential to improve the overall performance of these vehicles. In this paper, a Z-source inverter for fuel cell vehicle application is examined under three different scenarios. 1. a ZSI with Si IGBT modules, 2. a ZSI with hybrid modules, Si IGBTs/SiC Schottky diodes, and 3. a ZSI with SiC MOSFETs/SiC Schottky diodes. Then, a comparison of the three scenarios is conducted. Conduction loss, switching loss, reverse recovery loss, and efficiency are considered for comparison. A conclusion is drawn that the SiC devices can improve the inverter and inverter-motor efficiency, and reduce the system size and cost due to the low loss properties of SiC devices. A comparison between a ZSI and traditional PWM inverters with SiC devices is also presented in this paper. Based on this comparison, the Z-source inverter produces the highest efficiency.

SiC versus Si—Evaluation of Potentials for Performance Improvement of Inverter and DC–DC Converter Systems by SiC Power Semiconductors

Switching devices based on wide bandgap materials such as silicon carbide (SiC) offer a significant performance improvement on the switch level (specific on resistance, etc.) compared with Si devices. Well-known examples are SiC diodes employed, for example, in inverter drives with high switching frequencies. In this paper, the impact on the system-level performance, i.e., efficiency, power density, etc., of industrial inverter drives and of dc-dc converter resulting from the new SiC devices is evaluated based on analytical optimization procedures and prototype systems. There, normally on JFETs by SiCED and normally off JFETs by SemiSouth are considered.